Vol 58 Issue 1 January 2014

Published by Johnson Matthey Plc

A quarterly journal of research on the science and technology of the platinum group metals and developments in their application in industry

Vol 58 Issue 1 January 2014 www.platinummetalsreview.com

Platinum Metals Review is published by Johnson Matthey Plc.

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No warranties, representations or undertakings of any kind are made in relation to any of the content of this publication including the accuracy, quality or ﬁ tness for any purpose by any person or organisation. E-ISSN 1471-0676 •Platinum Metals Rev., 2014, 58, (1), 1• Platinum Metals Review A quarterly journal of research on the platinum group metals and developments in their application in industry http://www.platinummetalsreview.com/

JANUARY 2014 VOL. 58 NO. 1 Contents

Platinum Metals Review is Changing in 2014 2 An editorial by Sara Coles

Focused Ion Beam and Nanomechanical Tests for High Resolution 3 Surface Characterisation: New Resources for Platinum Group Metals Testing By Marco Sebastiani, Marco Renzelli, Paolo Battaini and Edoardo Bemporad

High Temperature Thermomechanical Properties of 20 Titanium-Rhodium-based Alloys Containing Scandium By Yurii V. Kudriavtsev and Elena L. Semenova

EuropaCat XI 31 A conference review by Silvia Alcove Clave, Francesco Dolci, Peter R. Ellis and Cristina Estruch Bosch

The Discoverers of the Isotopes of the Platinum Group of Elements: 38 Update 2014 By John W. Arblaster

PGMs in the Lab: Platinum Group Metals in Polyoxometalates 40 Featuring Ulrich Kortz

Publications in Brief 43

Abstracts 46

Patents 50

Final Analysis: Effects of Platinum Group Metals Doping 54 on Stainless Steels By Andrew Fones and Gareth D. Hatton

Editorial Team: Sara Coles (Assistant Editor); Ming Chung (Editorial Assistant); Scott Turnbull (Scientiﬁ c Information Assistant) Platinum Metals Review, Johnson Matthey Plc, Orchard Road, Royston, Hertfordshire SG8 5HE, UK Email: [email protected]

Editorial Platinum Metals Review is Changing in 2014

Platinum Metals Review, Johnson Matthey’s journal will still be free to access and free to publish; all of of research on the science and technology of the the costs are absorbed by Johnson Matthey as part platinum group metals (pgms) and developments of its service to the community. in their application in industry, has a long and On behalf of Johnson Matthey I would like to proud history having been published by Johnson thank all of Platinum Metals Review’s readers, Matthey since 1957 – continuous publication for 58 authors, reviewers, Editorial Board members and years. other stakeholders for your input over the years From mid-2014, regular readers will see changes, not and I hope that you will be interested in continuing least of which will be to the name of the journal: your contribution to the success of the journal in Platinum Metals Review will become the Johnson future. Matthey Technology Review. Please look out for further announcements, This change refl ects our intention to cover a including the wider range of topics which we will much wider range of technologies than at present. begin to cover, via our website, Twitter, email and in Today, Johnson Matthey is more than just a precious the next issue of the journal. We hope you are as metals company, with interests which extend to excited as we are about this opportunity to greatly base metal catalysis, products for pharmaceutical expand the range of subjects that will fi nd a home, and medical applications and battery materials, and an interested audience, in the Johnson Matthey among others. These technologies will also begin Technology Review. to feature in future issues of the journal alongside pgms, which remain indispensable for so many SARA COLES, Assistant Editor applications and processes. The format of a peer-reviewed scientifi c journal, Platinum Metals Review which has worked well for us in the past, will remain as it is important to maintain a high quality Contact Information publication that our readers will want to read and Johnson Matthey Plc cite. Orchard Road We welcome and encourage submissions from all Royston who are working in fi elds of interest to the journal, Hertfordshire which is provided as a service to the community SG8 5HE who work with pgm and now, non-pgm science and UK technology in a range of relevant fi elds. The journal Email: [email protected]

Focused Ion Beam and Nanomechanical Tests for High Resolution Surface Characterisation: New Resources for Platinum Group Metals Testing

Use of two high resolution techniques allows process optimisation and prediction of in-service behaviour

http://dx.doi.org/10.1595/147106714X675768 http://www.platinummetalsreview.com/

By Marco Sebastiani and Marco Renzelli Recently, the increasing importance and scope of nanotechnology has extended the need for high University of Rome “Roma Tre” Engineering Department, resolution characterisation tools beyond their traditional Via della Vasca Navale 79, 00146 Rome, Italy domains. As a consequence, advanced high-resolution tools at the nanoscale are now increasingly used in research and development (R&D) activities, offering the Paolo Battaini chance for a better understanding of submicron feature 8853 SpA Via Pitagora 11, I-20016 Pero, Milano, Italy size dependence. This paper gives an overview of the synergic application of two high resolution techniques on the platinum group metals (pgms): focused ion beam Edoardo Bemporad* (FIB) coupled with electron beam imaging, milling and deposition techniques; and nanoindentation testing. University of Rome “Roma Tre” Engineering Department, Via della Vasca Navale 79, 00146 Rome, Italy After a brief description of both techniques (architecture, probe-sample interaction basics and operation *Email: [email protected] modes), the effectiveness of this combined approach is demonstrated for microstructural and nanomechanical investigations on very small samples. The advantages are low cost, fast and site-specific sample preparation for transition electron microscopy (TEM) analysis; study of the mechanical hardening effect on microstructure and hardness profile at the micron scale; failure analysis; and understanding of plasticity and elasticity behaviour. Two specific case studies related to a platinum-copper alloy for jewellery use and a platinum-rhodium alloy for sensor manufacturing are presented and discussed.

1. Introduction The structural characterisation of engineered surfaces is of increasing importance due to the growing application of surface modification processes and coating techniques, which are usually applied to improve either mechanical or functional surface performance. Some examples include surface hardness, load bearing capacity, impact bearing capacity, wear resistance, specific surface area (related to surface free energy and chemical reactivity),

electrical resistivity, thermal conductivity and ‘smart’ Moreover, some analysis on cross-sections and even optical properties (1). TEM lamellae extraction are virtually nondestructive, The development of nanostructured materials and as the sample size required is just a few cubic microns. the increasing use of nanosystems and nanostructures In this paper, two examples are outlined to show how make the use of advanced procedures for nanoscale the combined use of nanomechanical testing and high mechanical characterisation necessary to understand resolution microscopy can help gain understanding of chemical and physical phenomena at this scale (2). the processing mechanisms and in-service behaviour The in-service macroscale mechanical behaviour of components. In particular: of micro- and nanocrystalline metals (for example, yy Cross-section cut-and-view for rapid their fracture and plastic deformation behaviour) is microstructural investigation (grain size and strictly related to the complex interactions between inclusions) on very small samples without any the different micro- and nanostructural features sample preparation or preprocessing (dualbeam) (for example dislocation sources, grain boundaries yy Low cost, fast and site-specific sample preparation and nanoscale porosity). These latter aspects are for TEM analysis (dualbeam) particularly critical in the advanced metallurgy of yy Deformation mechanisms at the nanoscale pgms alloys, where the actual role of phase transitions, (dualbeam and nanoindentation) the microstructural evolution of interfaces during yy Mechanical hardening effect on microstructure processing and the correlation with their mechanical and hardness profile at the micron scale properties are not yet completely understood. (dualbeam and nanoindentation) The in-service performance of such materials yy Separate measurement of elastic modulus, is dependent on the evolution of nano- and apparent hardness, true hardness, plasticity and microstructural features during processing, including hardening behaviour (nanoindentation). development of nanodispersed phases, grain growth, The article will focus on two case studies, explaining evolution and composition of grain boundaries, the importance of the combined use of dualbeam and dislocation density and distribution. Therefore an nanomechanical testing for the correct evaluation understanding of the correlation between the micro- of mechanical and functional performances of or nanostructure and the mechanical properties nanostructured systems in the pgms: of a material is critical for the development of yy Order hardening of platinum-5 wt% copper new and improved materials. High resolution alloys: microstructural and nanomechanical microscopy analysis together with nanomechanical characterisation for this alloy used in jewellery; characterisation are powerful tools that can allow yy Influence of process history on microstructure such understanding. and mechanical properties of platinum-rhodium The present paper gives an overview of the alloys, used in thermocouples. synergic use of two high resolution techniques, In both cases, it will be demonstrated that which are expected to be established as enabling nanoindentation testing can give valuable information technologies for improving the current understanding on the microstructural changes due to phase transition of the correlations between process, microstructure, and intragrain microstructure. In addition, the properties and performance for precious metal alloys. combined use of FIB/scanning electron microscope These are: (SEM) and TEM techniques could help to understand yy FIB coupled with electron beam for imaging, how and why microstructural changes due to heat milling and deposition (referred to as ‘dualbeam’ and/or mechanical treatments affect the mechanical (3–5)) behaviour of samples. yy Nanoindentation (6–12) for hardness measurement with a very low load. 1.2 Brief Introduction to Focused Ion Beam (FIB) Techniques 1.1 Advantages of the Techniques FIB technology was first introduced in the 1980s in the A key advantage of these two techniques (FIB/SEM and semiconductor industry. FIB instruments derive their nanoindentation) for high-technology manufacturing design from the SEM. However while SEM instruments is that both are very site-specific and virtually artefact use electrons that are accelerated and focused on a free in measuring as well as in imaging or shaping surface, FIB uses ions (usually gallium). The image samples in order to expose the region of interest. is derived from secondary electrons resulting from

the particle irradiation. The use of ions means that it imaging and at high beam currents (of the order of is not only possible to image the surface but also to nA) for site-specific milling. mill it, using sputtering phenomena to remove material. FIB techniques can be also used for TEM lamella From an engineering point of view, the two instruments, preparation: a finished electron transparent portion albeit similar in concept, are different in construction: of the sample (usually 5 μm × 20 μm) is obtained by the high mass of the ions requires electrostatic lenses, FIB milling (performed at 30 kV by using a decreasing instead of electromagnetic lenses as used in SEM (3–5). sequence of ion milling currents, from 9 nA down to The new generation of FIB equipment is equipped 0.28 nA for the final polishing) and then carried by a with both an ion beam column and an electron micromanipulator on a sample holder to be inserted beam column (SEM), providing imaging of the ion into the TEM microscope: this procedure at present beam milling process. In this case the instrument is represents the best site-specific and artefact-free TEM called a dualbeam microscope (Figure 1(a)). It can sample preparation methodology. Figure 2 illustrates be seen from Figure 1(a) that the instrument can how a dualbeam can be used to prepare site specific thin use the electron and ion columns at the same time; sections for high resolution TEM imaging and analysis. considering that the resolution of the FIB is 5 nm, it is possible to mill the surface in real time with nanometre 1.3 Brief Introduction to Nanoindentation resolution, working it with ions and observing it with Testing electrons, as in Figure 1(b). In dualbeam with in situ Nanoindentation testing (6) has been widely adopted SEM three dimensional tomography can be obtained in the last two decades for the surface mechanical by the slice-and-view process (3–5). An additional characterisation of bulk materials and coatings. feature of FIB is the capability to deposit thin films (for The method involves the controlled penetration example, made from Pt or carbon) by ion- or electron- of a diamond indenter of known shape into the assisted chemical vapour deposition (CVD), as shown material. Usually, a three-sided pyramidal indenter in Figure 1(b). (Berkovich) is used in conventional nanoindentation. FIB milling can be performed on hard, soft and By measuring the load and displacement during the biological materials with minimal artefacts (3–5). loading and unloading parts of the test, hardness (i.e. Some Ga atom implantation and amorphous layers resistance to plastic deformation) and elastic modulus will typically be observed but these artefacts can be can be calculated (6, 7). In this way, a very accurate limited to a thickness of a few nanometres by careful characterisation of the elastic and plastic properties selection of the milling parameters (mainly current at a material’s surface can be achieved, with a depth and voltage). FIB systems use a focused beam of Ga+ resolution and a lateral spatial resolution of the order of ions at low beam currents (of the order of pA) for a few nanometres.

(a) (b) SEM

FIB 52º

~4.1mm

10 µm

Fig. 1. (a) Schematic of dualbeam FIB/SEM equipment; (b) an example of a cross-section by FIB. A thin layer of Pt is deposited before ion milling

(a) (b) (c)

10 µm 20 µm 5 µm

Fig. 2. Sequence for TEM lamella preparation by FIB techniques for a Pt-Cu alloy: (a) FIB milling of a thick lamella and cutting section (~300 nm, milled at 0.92 nA); (b) lift-out of the lamella by the micromanipulator; (c) welding of the lamella on the TEM sample holder and final thinning to electron transparency (~80 nm, at a current of 0.28 nA)

During a basic indentation test an ideally rigid Aa=+ha2 ha++ha14//h 18+ ... (ii) indenter of known geometry is pressed against the cc0 12cc3 c sample surface up to a controlled maximum load, following a controlled loading (or displacement) The contact depth is defined as follows (see also rate. When the indenter is driven into the material, Figure 3(a)): both elastic and plastic deformation processes occur, P producing a hardness impression that conforms to the hhc =−ε ⋅ (iii) S shape of the indenter to a certain contact depth, hc (Figure 3(a)). The hardness H is easily obtained as a function of The coefficient ε can range between 0.72 and 1; load (or penetration depth) by the following equation: a value of 0.75 is usually adopted for the Berkovich indenter. P H = (i) The contact area expressed in Equation (ii) is A c evaluated by calibration on a certified fused silica reference sample, performed before and after each where P is the maximum load and Ac is the indenter series of tests. As the indenter is removed from the projected contact area, which is given as a polynomial surface, a purely elastic recovery phenomenon occurs, function of the contact depth, hc, for a Berkovich indenter: thus giving a measurable unloading elastic contact

(b) (a) Load (P) 500 450 Loading 400 curve 350 Ac=f(hc) 300 250 Unloading h t hc Y 200 curve 150 100

Load on sample, mN 50 0 0 1000 2000 Displacement into surface, nm

Fig. 3. (a) Contact geometry usually adopted in modelling sharp indentation testing. The equivalent cone angle ψ is equal to 70.3º for the Berkovich and Vickers indenters; (b) an example of a load-displacement curve for an amorphous fused silica reference sample

stiffness, which can be analytically correlated to both scale effects in mechanical behaviour of small scale the material’s and the indenter’s elastic properties by specimens (11) and residual stress (12, 13). the use of the Sneddon solution for the contact on an In the case of metals, significant dependence of axisymmetric elastic body on a flat surface (6): the measured hardness on the applied load is usually observed, even if a self-similar indenter is used for π S Er =⋅ (iv) testing (for example, a pyramidal indenter). This 2β A experimental evidence, which is usually referred to as ‘indentation size effect’ (ISE), is not only due to the S = dP/dh is the elastic contact stiffness which is effects of surface preparation (i.e. surface hardening) evaluated, after fitting the upper portion (usually 50%) and/or indenter tip blunting (i.e. not perfectly sharp of the unloading curve to a power-law relation (Oliver- indenters), but also to a real ‘material scale-dependent Pharr method (6)), as the slope of the unloading curve plasticity’, that has been related to subsurface at maximum load Pmax. modifications of the dislocation density across the Er is the reduced modulus (which takes into account plastically deformed volume which is created during both the elastic deformation of sample and indenter), indentation. given by: The most diffused model to understand ISE was proposed by Nix and Gao (10). The model is based 22 1 ()11−ννs ()− i on a simple concept, that ‘geometrically necessary = + (v) E * Es Ei dislocations’ (GNDs) must be created in the plastically deformed volume (beneath the indenter) to where Ei and νi are, respectively, the Young’s modulus accommodate the deformed material from the surface. and the Poisson ratio of the indenter. β is a numerical The GNDs exist in addition to the other statistically correcting factor equal to 1.034 for a Berkovich stored dislocations (SSDs), which are usually present indenter, which is introduced to correct for the lack in any polycrystalline metal. The additional amount of symmetry of the indenter with respect to the ideal of GNDs gives rise to an additional hardening effect, conical shape. As recently reviewed by Oliver and which is higher as the size of indentation decreases, Pharr (6), values in the range of 1.0226 ≤ β ≤ 1.085 can thus explaining the observation of increasing hardness be found in the literature; in the present work the value with decreasing applied load. of 1.000 is adopted, as suggested by the ISO 14577-1-2 Starting from this idea and assuming a conical standard. rigid indenter, Nix and Gao came out with a simple Equations (i)–(v) give a short synthesis of the Oliver- equation describing the variation of hardness as a Pharr method (see also Figure 4), which is conventionally function of the penetration depth during indentation: adopted for the analysis of hardness and elastic modulus * from a generic nanoindentation test. h HH=+0 1 (vi) An interesting modification of the conventional h nanoindentation is the so called ‘continuous stiffness measurement’ (CSM) method. In the CSM method where H0 is the macroscale hardness and h* is a (7), the contact stiffness S is dynamically measured characteristic length scale, which depends both on the during indentation and continuous hardness/depth material’s properties and the indenter geometry. and modulus/depth curves are obtained using Equations (i)–(v). 2. Case Study 1: Microstructural and Apart from the most conventional analysis, Nanomechanical Characterisation of nanoindentation testing has been used for the Pt-5%Cu Order Hardened Alloys evaluation of several other surface mechanical Pt-5 wt% Cu alloys are used in jewellery mainly properties, such as yield strength and strain hardening because the addition of Cu significantly improves behaviour of metals (7, 8), damping and internal the mechanical properties compared to pure Pt, friction in polymers (i.e. storage and loss modulus), particularly its resistance to plastic deformation (i.e. activation energy and stress exponent for creep (8), yield strength and hardness); it is also known that fracture toughness of bulk ceramics and coatings heat treatment of Pt-5 wt% Cu alloys can result in (9), adhesion of thin films and work of adhesion (11), a further increase of indentation hardness (often

t h = h = 0.75 for a ε Berkovich indenter Area function is obtained by independent measurements on fused silica reference sample Fitting of the unloading curve and first derivative at for frame stiffness) correction (+

i i E c S 1–v

s s

p √ 2 √A = ––

t P S ) * 1 1–v E* E –– c –– = ––– + E h ε ( h=h dP dh = f c OUTPUT = h – A c = –– = –– h S c P A (metals) = ––

H H 3 –– INPUT ≈ y σ S 600 t h slope = 500 h s h = 0.75 c ε h 300 400 for c h 5 µm P Y Displacement, nm c A 100 200 0

30 20 10 Load, mN Load, Fig. 4. Oliver and Pharr method for hardness elastic modulus evaluation by nanoindentation (7)

measured by Vickers microhardness testing) (14). diamond indenter, using an Agilent G200 Nano This phenomenon is related to the fact that the Pt-Cu Indenter, in a CSM mode under a constant strain binary system forms an ordered structure (described rate of 0.05 s–1 and a maximum penetration depth by the CuPt7 model) from the disordered face- of 2000 nm (other test and fitting parameters were centred cubic (fcc) solid solution, in the composition chosen according to ISO 14577-1-2 standards) (18). range 12–25 at% Cu (14). Cross-section SEM-field emission guns (SEM-FEG) It has also been previously reported that the microstructural observation and TEM-SAED analyses order-disorder transition can be strongly enhanced were performed after FIB sample preparation in a by inducing a certain quantity of microstructural dualbeam (FEI Helios Nanolab 600). defects in the structure, for example, by quenching or Cross-sections were obtained by FIB milling after a by plastic deformation (14). preliminary in situ Pt deposition to protect the surface A recent paper (15) reports a study of the order- layers during ion milling; the sectioning process disorder transition in Pt-5 wt% Cu alloys using TEM- consisted of a preliminary high ion current milling selected area electron diffraction (SAED) probing, (9 nA) followed by cleaning the section (0.9 nA) until showing that initially quenched specimens were the desired section was obtained. Microstructural characterised by relatively larger ordered domains observation was performed using both the ion probe after heat treatment and by a lower increase of (maximum microstructural contrast) and the electron Vickers hardness in comparison with cold plastically probe (maximum morphological contrast), secondary deformed samples. Nevertheless, a deeper analysis of electrons were detected in both cases. The dualbeam the influence of the mechanical hardening process technique was also used to extract electron transparent on the microstructural and structural characteristics foils for TEM (Philips CM 120, LaB6 analytical). TEM of order-disorder transition is still required, in order to analyses consisted of bright field high magnification discover the optimal cold working process in terms observation followed by SAED, performed both at the of induced plastic strain and induced modification surface of the TEM foil and at its centre. of hardness and of hardening coefficient, which can guarantee the maximum increase of hardness after 2.2 Results and Discussion heat treatment. Furthermore, there is still a strong The results of the nanoindentation testing are necessity for the development of more reliable reported in Figure 5 and summarised in Table I. and accurate procedures for the technological The nanohardness profiles presented in Figure 5 assessment of phase transitions after heat treatment. clearly confirm that the hardness is significantly In this section, an innovative procedure for the increased after heat treatment. Furthermore, in this mechanical and microstructural characterisation case, the presence of a surface hardened layer is of Pt-Cu order hardened alloys is presented, observed for penetration depths lower than 500 nm. essentially based on the combined use of micro- and Nanoindentation testing allows a more detailed nanoindentation testing and ISE modelling, dualbeam analysis of this effect to be performed: it is very and TEM techniques. It is shown that the correct important to note that the hardness profiles for both modelling of micro- and nanoindentation hardness samples have a very similar shape, i.e. a very similar results coupled with high resolution dualbeam and skin effect is observed in both cases. TEM observations can give deeper information on This observation suggests that the microstructure the actual influence of the preliminary cold working derived from the cold working process (which likely process on the order hardening transition. involves the formation of a surface hardened layer) is completely maintained after heat treatment, because 2.1 Experimental Details the same hardness gradient is observed in both One as cast Pt-5 wt% Cu ingot was subjected to cases. This also means that neither recrystallisation homogenisation at 1000ºC for 15 h and then plastically nor changes of grain size occurred during the heat deformed by uniaxial compression (milled) with a treatment at 290ºC, suggesting that the order-disorder thickness reduction of 75%. From the milled plate phase transition is realised at a subgrain level with no two samples were cut. One of these two samples significant modification of dislocation density. was heat treated at 290ºC for 3 h and finally cooled Another relevant observation comes from SEM- in air. The hardness of both samples was studied by FEG imaging of the nanoindentation marks. Figure 6 nanoindentation testing by means of a Berkovich shows the rounded shape of the indent lateral profile.

(a) 6.5 6 5.5 5 4.5 4 3.5 3 2.5 2

Nanohardness, GPa Cold worked and heat treated at 290ºC 1.5 Only cold worked 1 0.5 0 0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 Displacement into surface, nm

(b) 1.6 H 2 h* –– = 1 + –– 1.4 ( H 0 ) h

1.2

1 2 ) 0

H 0.8 / H = 3.72 GPa H 0 ( Cold worked and heat treated at 290ºC * 0.6 {h = 0.077 µm

0.4 H = 2.76 GPa Only cold worked 0 {h* = 0.186 µm 0.2

0 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8

1/h, µm–1

Fig. 5. (a) Nanoindentation hardness depth for both Pt-Cu samples under investigation; (b) analysis of hardness data through the Nix-Gao ISE model. Hardness is confirmed to be higher for the heat treated sample

From Figure 6(b) it can be clearly seen that for hardness, but also the hardening coefficient of the the heat treated sample there was a higher amount sample. As reported earlier (8), a different hardening of piling up at the edge of indentation. This suggests coefficient usually involves a different amount of that the heat treatment may have influenced not only piling-up during indentation.

Table I Summary of Results for the Micro- and Nanomechanical Characterisation of Platinum-5 wt% Copper Samples

Nix-Gao parameters (Equation Hardnessa, GPa Modulusa, GPa * (vi)) (H0; h ), GPa; µm

Cold worked sample 3.08 ± 0.11 205.1 ± 4.7 2.76; 0.186

Cold worked and heat 3.88 ± 0.21 215.2 ± 7.1 3.72; 0.077 treated sample a Average in the penetration depth range of 300–900 nm

(a) (b)

5 µm 5 µm

Fig. 6. Dualbeam (SEM column) micrographs on Berkovich nanoindentation marks for: (a) cold worked sample; (b) cold worked and heat treated sample. A higher amount of piling up is observed in case of the heat treated sample, thus suggesting that order hardening also involves a modification of the hardening coefficient

This observation is confirmed by an analysis of the observed pile-up during indentation. As widely the hardness data using the Nix-Gao ISE model reported in the literature, piling up always involves an (10), where a significantly different value of theh * over-estimation of the measured elastic modulus, due parameter is found (see Table I and Figure 5(b)) , to incorrect evaluation of the real contact area by the thus suggesting that the two samples may have a Oliver-Pharr method (7). The observed difference in different hardening coefficient. This leads to a very the elastic modulus is therefore likely not to be a real important conclusion: the hardening behaviour (not effect, thus suggesting that modulus does not change only hardness) of the heat treated sample is modified, significantly after the heat treatment (as expected). which can have a significant effect on workability In both Figures 8 and 9, the left column refers and on service performance of materials heat treated to the cold worked sample, while the right column in such a way. refers to the cold worked and heat treated sample. The results of the indentation modulus profile are Dualbeam characterisation analysis clearly shows reported in Figure 7, where elastic modulus is shown that the microstructure and microscale morphology to be constant with penetration depth and does not of both samples are very similar. In both cases, depend on sample microstructure (as expected). a strongly oriented (biaxial) grain structure is The elastic modulus seems to be ~5% higher for the observed, which is likely to be a consequence of the heat treated sample, however this is not considered cold forming process. These results confirm that the statistically significant. This difference is likely due to microstructure of the sample is not modified by the

240

220

200

180

Cold worked and heat treated at 290ºC 160 Only cold worked 140 Elastic modulus, GPa

120

100 0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200

Displacement into surface, nm

Fig. 7. Elastic modulus as measured by nanoindentation testing for both samples heat treatment and that the order-disorder transition transition is usually observed only for seriously is likely to happen at a subgrain level. A similar plastically deformed samples and not for quenched result can be achieved by a careful analysis of the or as-cast samples. nanoindentation hardness profile. The results of TEM-SAED analysis on dualbeam 3. Case Study 2: Influence of Process prepared thin foils are reported in Figure 9. Figures History on Microstructure and Mechanical 9(a) and 9(e) show detail of the grain structure at Properties of Platinum-Rhodium Alloys the sample surfaces. It is clear that the grain structure Alloys of Pt and Rh (19, 20) are widely used in has been maintained almost identically after heat many industrial sectors, due to their high strength treatment and that the dislocation density is similar compared to pure Pt, good workability and very in both cases, confirming the results obtained good corrosion resistance even at high temperature. by nanoindentation and dualbeam cross-section Examples from industry include thermocouples observation. In addition, a very thin surface hardened for high-temperature measurement, clean and inert layer (characterised by a finer grain size) is clearly heating elements in experimental high-temperature shown in Figures 9(b) and 9(f). Figures 9(c)–(g) furnaces, components in the manufacture of glasses, show details of the intragrain morphology, which are catalyst gauzes and laboratory equipment (21–24). significantly different for the two samples. In the case The use of Pt-Rh alloys has been increasing due to of the heat treated sample the ordered domains are the fact that Rh dissolves in all proportions in Pt, thus clearly visible confirming that the phase transition forming a substitutional solid solution which usually happens at a subgrain level. involves an increase of hardness with no significant In addition, a complete change of dislocation loss of workability. distribution is evident in the ordered domain, However, there are still controversial results in suggesting that dislocations (or generally speaking, the literature on the actual phase evolution of all defects coming from plastic deformation) can be Pt-Rh systems at temperature below 1033 K. Some considered the main nucleation sites for the phase authors have proposed the presence of a miscibility transition. This explains why the order-disorder gap below 1033 K (19), which was not confirmed

(a) (c)

20 µm 10 µm 160.8 nm (cs) (b) (d)

1 µm 1 µm

Fig. 8. Dualbeam (FIB and SEM column) analysis of samples: (a) and (b) the cold worked sample; (c) and (d) the cold worked and heat treated sample. It is worth noting that the microstructure obtained after cold working is maintained after heat treatment, including the surface hardened layer

by other similar studies, thus suggesting that are strongly needed, with the main objective of finding further investigations should take place to achieve out the existing correlations between the observed a better and deeper understanding of the actual microstructures and the technological performance microstructural and phase evolution of Pt-Rh systems (for example, hardness) of the components. This data after heat treatment and cooling to room temperature can then be used to optimise the process parameters. (20). In this work, the usefulness of the above Another issue of interest is represented by the described procedure for the microstructural and observed tendency to oxidation of Rh after heat nanomechanical characterisation is demonstrated for treatment of Pt-Rh systems, which usually involves a Pt-10 wt% Rh wires. Two different industrially produced decrease in the indentation hardness of the samples; samples (which were expected to be identical) were in the case of industrially produced components investigated by high resolution microscopy techniques (for example, wires) the mechanisms of oxidation (dualbeam-TEM) and nanoindentation testing. A behaviour as a function of process parameters have correlation between the observed differences in terms not been completely investigated. These examples of indentation hardness and the actual microstructure suggest that innovative characterisation procedures is finally presented.

(a) (e)

200 nm 200 nm

(b) (f)

200 nm 200 nm

20 nm 20 nm

(d) (h)

Fig. 9. TEM-SAED analysis on dualbeam prepared thin foils: (a), (b), (c) and (d) cold worked samples; (e), (f), (g) and (h) cold worked and heat treated samples. High dislocation density is observed in both cases. Order hardening is observed at a subgrain level; (d) and (h) SAED patterns clearly show the change of crystal structure after heat treatment

3.1 Experimental Details A TEM lamella was realised at the external edge of Two sets of Pt-10 wt% Rh wires from two different each sample: one grain boundary was included at the producers, referred to as Sample 1 and Sample 2, were centre of each lamella, as reported in Figure 10. In investigated. The samples were nominally produced this way, all microstructural features influencing the by the same process, consisting of various stages of mechanical properties of the wires were able to be drawing and annealing from the initial ingot down investigated (for example, subgrain microstructure, to the final section of about 350 µm. Vickers hardness grain boundary oxidation, presence of precipitates at (applied load 100 gf) was preliminarily performed grain boundary or in the matrix and oxygen diffusion on both samples and a significant difference was from the sample edge). observed (as briefly reported in Figures 11(a) and Nanoindentation testing was used to evaluate 11(b)). In particular the Vickers hardness was about the subgrain hardness profile: one line of Berkovich 15% higher for Sample 2. indentation (maximum penetration depth 1 µm, CSM Starting from this preliminary result, characterisation mode, 0.05 s–1 constant strain rate) was realised across activities consisted of dualbeam-TEM microstructural the section of each wire. The measured hardness observations and nanoindentation testing. The ion profile was then compared to the observed grain beam was used at a current of 48 pA in the dualbeam structure. microscope to produce physical etching of the microstructure: in this way, the cross-section grain 3.2 Results and Discussion structure of the wires could be investigated by using Conventional metallographic observations are shown the ion source and detecting secondary electrons. in Figure 11. Dualbeam observation with ion source

(a) (b)

5 µm 5 µm

Fig. 10. TEM lamella for: (a) Sample 1; and (b) Sample 2. A grain boundary is clearly visible in both cases

(a) (b)

100 mm 100 mm

Fig. 11. (a) Cross-section of Pt-10 wt% Rh wire Sample 1: Vickers hardness HV00.1 = 92 ± 4 (optical microscope after polishing, ×50, applied force: 0.1 N); (b) cross-section of Pt-10 wt% Rh wire Sample 2: Vickers hardness HV00.1 = 105 ± 4 (optical microscope after polishing, ×50, applied force: 0.1 N)

of the cross-sections of both wires are reported in in comparison with data from microhardness testing Figure 12. In Figure 11(b) a coarser grain size is (performed at 100 gf): this suggests that some artefacts clearly observed for Sample 2. It is important to note are present during microhardness testing, likely due to that twins and low-angle grain boundaries can also be bending (or buckling) of the wires during indentation. revealed by using the FIB source for surface etching, For nanoindentation testing, the results reported in thus explaining why a larger number of grains are Figure 13 correspond to a penetration depth of revealed by this method compared to the conventional 300 nm (applied load of about 1 gf), to avoid any chemical etching and optical microscopy. The artefact due to buckling or bending of the wire. It is difference in observed grains was resolved with the also worth noting that some variation of nanohardness FIB, which showed that the large grains of Sample 2 is observed from one grain to another. are composed of smaller subgrains. A grain boundary is clearly visible for both samples. Nanohardness section profiles (Figure 13) In the case of Sample 2 the TEM lamella was likely confirmed a higher hardness for Sample 2. created at a twin boundary, as clearly identifiable Nevertheless, the observed differences are reduced in Figure 14. Looking at Figures 14(b) and 14(d),

(a) (b)

200 mm 100 mm

Fig. 12. Example of dualbeam analysis for: (a) Sample 1; and (b) Sample 2. Grain structure is clearly visible by using the ion source. The nanoindentation section profile is also clear in both cases. The TEM lamella was obtained at the sample edge corresponding to a grain boundary for each sample

Fig. 13. Nanohardness cross-section profiles for 2.5 both Pt-Rh wires under investigation (error bars have been removed for 2 clarity)

1.5

1 Pt-10 wt% Rh Sample 2 Nanohardness, GPa Pt-10 wt% Rh Sample 1 0.5

0 0 50 100 150 200 250 300 350 Radial position over the wire section, mm

(a) (c)

100 nm 100 nm

(b) (d)

20 nm 20 nm

Fig. 14. TEM-SAED analysis on Sample 1: (a) TEM, 120 kV, ×140.000; (b) (TEM, 120 kV, ×660.000) – (TEM- SAED, 120 kV, Z = [100]); and Sample 2: (c) TEM, 120 kV, ×230.000; (d) (TEM, 120 kV, ×660.000) – (TEM- SAED, 120 kV, Z = [114]) significant microstructural differences can be microstructure is observed in both cases. In this case, identified between the two samples. In particular, precipitates in the matrix of average diameter ~15 nm Sample 1 is characterised by the presence of are also observed for Sample 2, thus confirming that precipitates in the matrix (average diameter ~15 nm). the much finer subgrain microstructure that had been In Sample 2, a different intragranular microstructure observed in the as-received Sample 2 was likely due to can be observed, mainly characterised by very fine higher cooling rates during processing. precipitates dispersed in the matrix. The observed This example clearly explains how critical it is to difference in micro- and nanoindentation hardness properly control all parameters during the processing may therefore be due to differences of the intragrain of these components. The use of high-resolution phase distribution, which are likely strongly influenced microscopy was in this case absolutely necessary by cooling rates during processing. to examine the actual correlations between the It is also worth noting that no differences in terms of measured technological performance (for example, crystal structure (SAED) and composition (EDS) were indentation hardness), the actual microstructural detected between the two samples, thus meaning that features of samples and the main process parameters. observed differences are essentially due to different (or not completely controlled) cooling rates during 4. Conclusions some of the processing steps. This paper presents the application of high resolution, To verify this latter hypothesis, both samples were multitechnique and multiscale procedures to the subjected to a heat treatment at temperature of 450ºC nanomechanical characterisation of materials. for 1 h, followed by cooling in air. Results of the TEM It was observed that a comprehensive analysis are reported in Figure 15, where a similar characterisation of complex alloys can be achieved

(a) (b)

100 nm 50 nm

Fig. 15. (a) Sample 1 after heat treatment at 450ºC for 1 h (TEM, 120 kV, ×230.000); (b) Sample 2 after heat treatment at 450ºC for 1 h (TEM, 120 kV, ×380.000) – (Z = [100])

by the combination and synergic use of micro- and Such results clearly show how nanomechanical nanohardness testing and dualbeam-TEM techniques. testing in combination with high resolution Two case studies were reported relating to the microscopy can be usefully applied to the nanomechanical and microstructural characterisation characterisation of nanostructured systems for of an order hardened Pt-Cu alloy and a Pt-Rh wire functional (or non-mechanical) application and how alloy. In particular, the analysed case studies showed they can be a powerful tool for process optimisation that nanoindentation testing can give valuable and/or prediction of in-service behaviour. information on the level of microstructural changes Acknowledgments as a consequence of phase transition and intragrain This paper is dedicated to the memory of our wonderful microstructure. The use of dualbeam-TEM combination friend and colleague, Dr Paolo Battaini, who recently technique may finally help to understand how and passed away. The authors acknowledge the assistance why microstructural changes due to heat treatment of Daniele De Felicis during dualbeam characterisation affect the mechanical properties of materials. activities, carried out at the “Interdepartmental In the first case it was shown how the order- Laboratory of Electron Microscopy” (LIME), University disorder transition in Pt-Cu alloys can be evaluated ROMA TRE, Rome, Italy, http://www.lime.uniroma3.it. by indentation testing and that the analysis of hardness depth profiles can be extremely useful in suggesting the mechanisms of phase transition, which References were later proved using high resolution microscopy, 1 P. H. Mayrhofer, C. Mitterer, L. Hultman and H. Clemens, Progr. Mater. Sci., 2006, 51, (8), 1032 demonstrating that the order-disorder transition happens at a subgrain level only in previously cold 2 S. Zhang, D. Sun, Y. Fu and H. Du, Surf. Coat. Technol., 2003, 167, (2–3), 113 worked alloy. 3 M.W. Phaneuf, Micron, 1999, 30, (3), 277 In the second case the use of FIB showed that the results from optical imaging of the grains were 4 “Introduction to Focused Ion Beams – Instrumentation, Theory, Techniques and Practice”, 2nd Edn, eds. L. A. misleading, as were those from the microhardness test, Giannuzzi and F. A. Stevie, Springer Science+Business because they did not give correct information of the Media, New York, USA, 2005 real grain structure and the actual nanomechanical 5 L. A. Giannuzzi and F. A. Stevie, Micron, 1999, 30, (3), 197 properties of the Pt-Rh wires. High resolution TEM 6 W. C. Oliver and G. M. Pharr, J. Mater. Res., 1992, 7, (6), imaging pointed to a likely mechanism (differences 1564 in nanoprecipitates) explaining the differences in 7 W. C. Oliver and G. M. Pharr, J. Mater. Res., 2004, 19, hardness of the grains. With this work the existence of (1), 3 a miscibility gap and the absence of oxidation have 8 A. Bolshakov and G. M. Pharr, J. Mater. Res., 1998, been clearly shown, clarifying a point of contention 13, (4), 1049 between researchers in the field. 9 S. J. Bull, J. Phys. D: Appl. Phys., 2005, 38, (24), R393

10 W. D. Nix and H. Gao, J. Mech. Phys. Solids, 1998, 46, 17 D. Tabor, “The Hardness of Metals”, Oxford University (3), 411 Press, New York, USA, 1951 11 M. D. Uchic, D. M. Dimiduk, J. N. Florando and 18 ISO 14577-1/2:2002 ‘Metallic materials – Instrumented W. D. Nix, Science, 2004, 305, (5686), 986 indentation test for hardness and materials parameters 12 H. Bei, S. Shim, M. K. Miller, G. M. Pharr and E. P. George, – Part 1: Test method’ and ‘Part 2: Verification and Appl. Phys. Lett., 2007, 91, (11), 111915 calibration of testing machines’ 13 A. M. Korsunsky, M. Sebastiani and E. Bemporad, Mater. 19 K. T. Jacob, S. Priya and Y. Waseda, Metall. Mater. Trans. Lett., 2009, 63, (22), 1961 A, 1998, 29, (6), 1545 14 C. Mshumi and C. Lang, Platinum Metals Rev., 2007, 51, 20 Z. M. Rdzawski and J. P. Stobrawa, J. Mater. Process. (2), 78 Technol., 2004, 153–154, 681 15 M. Carelse and C. I. Lang, Scripta Mater., 2006, 54, 21 R. Wilkinson, Platinum Metals Rev., 2004, 48, (2), 88 (7), 1311 22 R. Wilkinson, Platinum Metals Rev., 2004, 48, (3), 145 16 ASTM Standard E384, ‘Standard Test Method for Knoop 23 R. Wilkinson, Platinum Metals Rev., 2005, 49, (1), 60 and Vickers Hardness of Materials’, ASTM International, West Conshohocken, PA, 2011 24 R. Wilkinson, Platinum Metals Rev., 2005, 49, (2), 108

The Authors

Marco Sebastiani, Marco Renzelli Paolo Battaini held Edoardo Bemporad PhD, is an Assistant received his Msc in a degree in nuclear is a nuclear engineer Professor of Materials Physics in 2010 at La engineering, had been and holds a PhD in Science at the Sapienza University a consulting engineer Materials Engineering. University of Rome of Rome. In January with 8853 SpA, He is a full Professor “Roma Tre”. His 2012 he started his and was a Professor of Materials Science research is focused on PhD in Engineering of Precious Metal and Technology at the surface engineering, at the University of Working Technologies University of Rome micron-scale residual Rome “Roma Tre”. at Milano Bicocca “Roma Tre”. He is the stress analysis and His interests lie in University, Italy, from author of more than nanomechanical advanced materials 2003 to 2011. He has 300 papers published testing of thin films production and been a recipient of the in international and and nanostructured characterisation, Santa Fe Symposium national journals, materials. He is the surface engineering, Research and and his interests lie author of more than PVD technologies, Ambassador Award. in structured and 40 papers in peer focused ion beam He died on 27th nanostructured reviewed international microscopy and September 2013. coatings, especially journals. nanomechanical for wear resistance, characterisation. corrosion resistance and high temperature oxidation.

High Temperature Thermomechanical Properties of Titanium-Rhodium-based Alloys Containing Scandium

Unusual shape memory effects observed in scandium-substituted alloy system

http://dx.doi.org/10.1595/147106713X675183 http://www.platinummetalsreview.com/

By Yurii V. Kudriavtsev* At high temperatures, the equiatomic binary compounds formed by Groups 4 and 8 transition metals G. V. Kurdyumov Institute of Metals Physics of the National Academy of Sciences of Ukraine (NASU) Vernadskiy Str. 36, are known to undergo martensitic transformation, 03142, Kiev, Ukraine which may be accompanied by a shape memory effect. Among these compounds, titanium-rhodium (TiRh) is *Email: [email protected] of special interest not only because it undergoes two martensitic transformations at high temperature, for one Elena L. Semenova** of which the shape memory effect has been observed, I. N. Frantsevich Institute for Problems of Materials Science but also because it demonstrates unusual shape of NASU Krzhyzhanovsky Str. 3, 03680, Kiev, Ukraine recovery behaviour at temperatures higher than 400ºC. The present work focuses upon the thermomechanical **Email: [email protected] and mechanical properties of 50 at% rhodium- scandium-titanium ternary alloys where Ti is substituted by Sc. These alloys were investigated for the first time using electrical resistance, dilatometry and three-point bending techniques in the temperature range 20ºC to 850ºC. It was found that the sample with 0.1 at% Sc exhibited full shape restoration in the ranges of both martensitic transformations at ~340ºC and ~750ºC. Two-way shape recovery was also observed. A small temperature hysteresis, desirable for alloys used in actuator applications, is present in TiRh and Rh-Sc-Ti alloys. Both TiRh and Sc-containing alloys exhibit continuity of the deformation process on cooling and shape restoration on heating in a wide range of temperatures. This feature of both TiRh and Rh-Sc-Ti alloys implies the possibility of their application in different heat-regulating elements at temperature ranges from room temperature to 850ºC.

Introduction An important field for the application of commercial alloys with shape memory effect is heat regulation. The alloys considered in this paper are being investigated for use in this application at high temperatures. Thermomechanical regulators have a number of advantages over electromechanical and electronic regulators, which are prone to failure under certain conditions. Regulators made from shape memory alloy, such as locking devices for control rods in

nuclear power stations, could provide more robust structure in TiRh at temperatures close to those 2 safety systems as they do not require any external obtained by the electrical resistance method, Ms power source for their activation, for example. ~340ºC. Anomalous behaviour of the sample when One of the challenges in high-temperature materials heated to 400ºC has been observed (6). science is to discover alloys that exhibit a high- The aim of the present paper is to study the influence temperature shape memory effect and to investigate of the third component, Sc, on the properties of TiRh- the conditions, including temperature range, under based alloys and particularly the thermomechanical which these properties are observed. The Rh-Ti behaviour of these alloys in the temperature range system is considered promising taking into account from ambient to 850ºC. Sc was chosen to substitute information on the alloys based on equiatomic phase Ti because it is similar to Ti by chemical properties (1–5) and data on the thermoelastic properties of the and also forms an equiatomic compound with Rh. equiatomic TiRh alloy at high temperatures (6). However the crystal structure of ScRh, which is of the There is limited literature data on the character and CsCl type (the same as the TiRh parent phase), is stable temperatures of transformation in near-equiatomic from subsolidus temperature to room temperature (7). Rh-Ti binary alloys. Such data are to a certain extent This makes it easy to follow changes that occur in conflicting, and concern mainly the crystal structure the Rh-Sc-Ti ternary alloys with increasing scandium of the phases formed (1–5). An X-ray study of TiRh content. in the temperature range from room temperature to Information on the effect of scandium on the 1000ºС showed that a high-temperature phase with a martensitic transformation (MT) in TiRh is almost caesium chloride (CsCl) type cubic crystal structure unknown. It was noted earlier that substitution of transformed to a phase with tetragonal structure at Ti by Sc would lead to a decrease of the martensitic 845 ± 20ºС when cooled from 1000ºС, then transformed transformation temperature (8). The phase relations in to a monoclinic phase at 83 ± 5ºС (3). Both transitions the ScRh-TiRh system have been studied elsewhere (9). were considered as second order transitions. It was noted that no domain of coexistence of cubic and Experimental tetragonal phases was observed, while the tetragonal The starting metals used for alloying were iodised character of the phase structure increased on cooling Ti, Rh powder (99.97 wt%), distilled Sc to prepare gradually from 845ºC to 83ºС. At temperatures lower the alloys with 0.1 at% and 1 at% Sc, and Sc metallic than 83ºС further distortion of the crystal lattice powder (chemical analysis: 1.3 wt% O and less than toward monoclinic symmetry took place. 0.15 wt% of metal admixture) to prepare the remaining Observed temperature intervals of three alloys. Before melting the alloys, the rhodium powder modifications of TiRh (3) confirmed previously was sintered in vacuum at 1200ºC and melted in an arc published data (2) that the TiRh phase crystal structure furnace in order to avoid sputtering during alloying. at 700ºС is tetragonal and of the AuCu type, while at The alloys with 0.1 at% and 1 at% Sc were melted room temperature the phase is monoclinic with lattice directly from the components and those with 2.2 at%, parameters different from those previously given (3). In 3.5 at%, 16.7 at% and 21 at% Sc were melted from the alloys with compositions deviating from stoichiometry ligature (the Sc-Rh binary alloys) with additions of towards 10 at% Rh content, according to the Rh-Ti titanium in an arc furnace with a non-consumable phase diagram, a phase with orthorhombic crystal tungsten electrode on a water-cooled copper hearth structure was observed at room temperature (2) within under an atmosphere of purified argon gas. The ingots the homogeneity range of the equiatomic phase (4, 5). were melted four times to ensure a complete melt. The Two transformations in TiRh were revealed by weight losses on melting were small (below 0.5 wt%) an electrical resistance method with temperatures so nominal compositions are reported. that differ from those previously obtained (3, 6) Samples of the six alloys were prepared along the (Figure 1(a)). Both transformations occurred almost ScRh-TiRh section. The as-cast alloys were investigated without hysteresis. The fact that they are clearly by electrical resistance and dilatometry tests. The separated by temperature (6) puts in doubt the electrical resistance was measured by the four-probe interpretation of the transformation as a second order method with continuous heating of the sample at transformation (3). a rate of 20ºC min–1. The change in sample length

The shape memory effect accompanies the (l20ºC = 14.7 mm) on heating and cooling in the dilatometry formation of a phase with a monoclinic crystal test was measured by an induction micrometer ‘Micron-02’

1 1 (a) 1 1 Ms ≤ Af 2 2 Mf ≤ As Ms ≤ Af M2 ≤ A2 1.3 f s 0

r 1.2 / r 1.1

0.9

–200 –100 100 200 300 400 500 600 700 800 900 Temperature, ºC

1 1 Ms ≤ Af (b) 1 1 2 2 Mf ≤ As 1.3 Ms ≤ Af M2 ≤ A2 1.2 f s

0 1.1 r / r

0.8 0.7 0.6

–200 –100 100 200 300 400 500 600 700 800 900 Temperature, ºC

r 1.1

0.8 0.7

–200 –100 100 200 300 400 500 600 700 800 900 Temperature, ºC

Fig. 1. Dependence of electrical resistance on temperature in ScRh-TiRh alloys: (a) TiRh; (b) Rh-0.1 at% Sc-Ti; and (c) Rh-1 at% Sc-Ti supplied by All-Union company ‘Stankoimport’, that was placed in a quartz holder. Thermomechanical Moscow, Russia, with accuracy ±0.1 micron. The properties of the alloys were examined using the three temperature of each sample was measured with a point bending technique by thermocycling through the chromel-alumel thermocouple welded to the sample transformation range during cooling under load and

heating after unloading (10). Thermomechanical curves process of structural transformation an intermediate were taken several times for each sample at different phase with a crystal structure similar to the R-phase in loads. The sample sizes were 0.4 × 0.4 × 10 mm (alloys with TiNi might form first (premartensitic transformation) 0.1 at% and 1 at% Sc) and 0.4 × 1.5 × 8 mm (alloys with (11). The second MT was identified by a change in the 2.2 at% and 3.5 at% Sc). The loads varied between slope of the resistance curve. The critical temperatures 50 g and 375 g. The sample of the alloy with 0.1 at% of the martensitic points in the forward and reverse Sc underwent more detailed investigation in the transformations coincide. temperature range which covered both transformations With increasing scandium content in the alloys to according to data on electrical resistance. The sizes of 16.7 at% Sc only one transformation was observed the sample and the load applied in this experiment in the resistance curve at approximately 400ºC, are presented and discussed together with the results. a temperature significantly lower than the first The alloys were characterised by X-ray diffraction transformation in alloys with lower scandium content (XRD) and microstructure analyses and the results are (Figure 2(c)). The shape of the alloy curve on cooling presented elsewhere (9). repeated that for alloys with 2.2 at% and 3.5 at% Sc (Figures 2(a) and 2(b)). Tests on the alloy with 16.7 at% Results and Discussion Sc at temperatures below room temperature (down Electrical Resistance to –196ºC) showed the absence of any effect. This The TiRh resistance curve shows two transformations confirms the assumption that with increasing content in the solid (Figure 1(a)). The transformation at of scandium in the alloys the second transformation 1 ~750ºC ( Ms ), of small intensity and without hysteresis, disappeared instead of lowering its temperature. is indicated by a point of inflection on the curve of According to X-ray analysis this alloy has a tetragonal 2 resistance. The transformation at ~340ºC ( Ms ), of crystal structure of AuCu type at room temperature greater intensity, occured with a small hysteresis: the (9). Thus, it may be concluded that the effect observed change in electrical resistance reached ~10%. on the resistance curve of the alloy with 16.7 at% Sc Investigation of MT in the ScRh–TiRh ternary alloys corresponds to the structural transformation CsCl → by the electrical resistance method was carried out on AuCu. Given the above as well as data on the electrical the samples with 0.1 at%, 1 at%, 2.2 at%, 3.5 at%, 16.7 at% resistance of TiRh and the alloys with lower scandium and 21 at% Sc (Figures 1(b), 1(c) and 2(a)–2(d)) . content, even without direct studies of the structure by The resistance curves for the first four alloys exhibit high-temperature X-ray analysis, it seems clear that the two transformations as was observed in the TiRh alloy. product of the first MT in all alloys of the ScRh-TiRh The heating and cooling curves of the alloys with system is a phase with a tetragonal crystal structure of 0.1 at% and 1 at% Sc almost superimpose in a wide the AuCu type. temperature range (Figures 1(b) and 1(c)). The effect Only a little variation in the slope of the resistance that corresponds to the second transformation is more curve of the alloy with 21 at% Sc was observed at pronounced in these alloys, although unlike that in TiRh about 200ºC, indicating that the intensity of the the transformation became almost without hysteresis. transformation decreases with increasing content of Given that the temperature of both transformations scandium in the alloys (Figure 2(d)). This alloy is two- slowly decreased with increasing content of scandium phased at room temperature: CsCl + AuCu (9). in the alloys, the resistance curves were observed to Thus, according to electrical resistance studies, behave similarly to TiRh. substitution of Sc for Ti in TiRh resulted in inhibition of In contrast to the curves of TiRh and the alloys with the second MT, the product of which would be a phase 0.1 at% and 1 at% Sc, a larger change in resistance with with monoclinic crystal structure, and in lowering the decreasing temperature was observed in the curves characteristic points of the first transformation, which for the alloys with 2.2 at% and 3.5 at% Sc (Figure 2) . disappeared with increasing content of scandium in 1 The first martensitic transformation ( Ms ) for these the alloys. alloys was clearer and more intense (Figures 2(a) The electrical resistance data concerning the two and 2(b)). Its temperature varied little with increasing stage transformations in the solid Rh-Sc-Ti ternary scandium content. At the initial transformation alloys and similar data on TiRh point to the existence of stage (740ºC–705ºC) a sharp change in electrical a two phase region in these alloys and are at variance resistance took place which is a characteristic of the with earlier conclusions (3) on the attribution of the transformation and gives reason to believe that in the transformation in TiRh to second order transformation.

(a) 1 Ms

1.1 2 Ms 0 r / r

1 20 100 200 300 400 500 600 700 800 900 1000 Temperature, ºC

(b) 1 Ms

1.1 2

0 Ms r / r

1 20 100 200 300 400 500 600 700 800 900 1000 Temperature, ºC (c)

1 Ms 1.1 0 r / r

1 20 100 200 300 400 500 600 700 800 900 1000 Temperature, ºC

(d)

1.1

1 Ms 0 r / r

1 20 100 200 300 400 500 600 700 800 900 1000 Temperature, ºC

Fig. 2. Dependence of electrical resistance on temperature in ScRh-TiRh alloys: (a) 2.2 at% Sc; (b) 3.5 at% Sc; (c) 16.7 at% Sc; and (d) 21 at% Sc

X-ray analysis of the ScRh-TiRh alloys with 0.1 at%–16.7 at% sample recovered its shape completely. In the range Sc showed regions of coexistence of phases of TiNi and 400ºC–200ºC the degree of deformation on cooling AuCu types as well as those of AuCu and CsCl types increased almost linearly. At a load of 100 g a bend (9). The electrical resistance data on TiRh-TiCo alloys occurred in the same temperature range (Figure 3(a), in which rhodium atoms were replaced with cobalt dashed lines) and the deformation of the sample atoms also demonstrated two stages of transformation proved to be twice as large in comparison with that at that were distinctly separated (6). In addition, some a load of 50 g; however the sample recovered fully on effects related to both transformations have been subsequent heating. Some residual plastic deformation observed on the thermal analysis curve of TiRh (9). All that occurred after loading and unloading of the these data strongly suggest that the transformations in sample at ~850ºC indicated the inconsistency of the TiRh and alloys based on it are first order. applied load with the elastic parameters of the sample at this temperature. Note the basic similarity of the Thermomechanical Tests thermomechanical curves of the alloy at different Thermomechanical tests were carried out for the loads (Figure 3(a)). alloys with 0.1 at%, 1 at%, 2.2 at% and 3.5 at% Sc The first transformation in the alloy containing 1 at% (Figures 3–5). There was a continuous bend for the Sc occurred in the same temperature range, 750ºC–650ºC sample with 0.1 at% Sc cooled under a load of 50 g (Figure 3(b)). In the temperature range from 650ºC to from ~900ºC–50ºC, and this was more intense in the room temperature the thermomechanical curve was range 750ºC–650ºC. On heating (after unloading) the almost linear. After unloading at 20ºC and subsequent

(a) 0.6 –P1

0.4

–P2 1 1 0.2 Ms≤Af

Height, mm +P2 0 +P1

100 200 300 400 500 600 700 800 900 Temperature, ºC

(b)

0.6 –P

0.4

0.2 1 1 Height, mm Ms≤Af

0 +P

100 200 300 400 500 600 700 800 900 Temperature, ºC

Fig. 3. Dependence of bending on temperature in ScRh–TiRh alloys: (a) 0.1 at% Sc; and (b) 1 at% Sc

(a) –P (b)

0.2 1 Ms 0 Height, mm +P

1 100 200 300 400 500 600 700 800 ≤900Af +P2 Temperature, ºC

(b) –P

1 0.2 Ms

Height, mm 0 +P

100 200 300 400 500 600 700 800 900 Temperature, ºC Fig. 4. Dependence of bending on temperature in ScRh–TiRh alloys: (a) 2.2 at% Sc; and (b) 3.5 at% Sc

+0.2 –P

2 Ms 0 Height, mm +P B –0.2

100 200 300 400 500 Temperature, ºC

Fig. 5. Dependence of bending on temperature in TiRh alloy heating to 850ºC, the sample’s shape restored fully. The thermomechanical curves of the alloys with 2.2 at% Cooling under load to the temperature of liquid and 3.5 at% Sc are similar to those of the alloys with nitrogen (–196ºC) showed that the Mf temperature 0.1 at% and 1 at% Sc (Figures 4(a) and 4(b)). The curves of the alloy was about 20ºC. Below this temperature in Figures 3–5 show the results of the thermomechanical cooling did not lead to additional deflection of the experiments. They show the presence or absence of the sample. The thermomechanical curves of both alloys shape memory effect and the unusual feature of the were without hysteresis except in the MT temperature expansion of shape recovery at temperatures between range for the transition CsCl → AuCu, where a small 20ºC–700ºC. Such a feature has not been observed in hysteresis occurred (Figures 3(a) and 3(b)). other alloys exhibiting a shape memory effect.

The unusual performance of TiRh alloy observed These partial curves demonstrate full shape during a study of its thermomechanical properties has restoration and almost no hysteresis between already been mentioned (6). No further experiments the forward and reverse transformations. Alloys had been carried out to study the sample’s behaviour exhibiting transformation with a very small when heated above the temperature of 400ºC and temperature hysteresis are known to be very useful it was only noticed that on reducing the elastic for actuator applications (12). Another quality of constants of the alloy with temperature, the bend of thermomechanical behaviour of the alloy with 0.1 at% the sample would remain constant or increase with Sc was observed earlier for the TiRh binary alloy in increasing temperature. Instead, during experiments the range of the second MT, which at the time was further straightening of the sample was observed. not explained (6). Upon heating of the sample free In order to study this anomalous behaviour, further of load gradual spontaneous bending took place, tests were carried out during the present study on a followed by outward bending on subsequent cooling sample of the ternary alloy with 0.1 at% Sc composition, throughout the temperature range corresponding to chosen for being closest to TiRh. The similarity of the the second transformation without a load (Figure 5, resistance curves of the two alloys (Figures 1(a) and B). A bend on cooling and heating curves of the 1(b)) together with the proximity of their compositions unloaded sample of the ternary alloy with 0.1 at% is believed to justify treating the test results obtained Sc was also observed in the temperature range of for the 0.1 at% Sc alloy as being comparable to those both transformations. (Figures 6(a), B, and 6(b)). expected for the TiRh binary alloy. Figure 6 presents In the case of the first transformation the effect was thermomechanical test curves of the 50 at% Rh–0.1 at% quite pronounced. This is thought to be evidence of Sc-Ti alloy in different temperature ranges. The full a two-way shape memory effect in these alloys. This bending curve taken in the range 20ºC–900ºC for the performance can be amplified by mechanical work sample with parameters 0.5 × 1.3 × 8 mm repeated the hardening of the samples at 20ºC. During abrading curves that were obtained in previous experiments of the 0.9 mm sample to the 0.5 mm sample it

(Figures 3(a) and 6(a)): under constant load (P1 = 250 g) spontaneously began to bend at room temperature. in the temperature range 750ºC–20ºC continuous bend One possible explanation for the simple shape of the on cooling and subsequent full shape restoration on bending and recovery shape curves in the 20ºC–750ºC heating of the sample were observed. More intense temperature range, while the resistance curves bending took place in the temperature range of the demonstrate two separate effects at 750ºC–650ºC first MT compared to that in the range of the second and 350ºC–250ºC corresponding to two martensitic 1 MT. While approaching the Ms point on the cooling transformations, is that the electrical resistance curve, a distinct bend was observed. This might be measurement technique registers the occurrence caused by the appearance of deformation martensite of only thermal martensite whereas bending of the overtaking the tetragonal thermal martensite at the sample may be caused by the formation of both 1 temperature Ms (Figure 6(a), A). thermal and deformation martensites. The latter The fact that the contribution of the second MT may appear above the Ms point as a result of bending to the overall bending is smaller than the first might load, as was observed in the case of alloys based on be due to insufficient loading. With decreasing TiNi (13). temperature, the coefficients of elastic deformation Thus despite the high temperature (~750ºC) the of all metals and alloys increase. Therefore for more first martensitic transformation in Rh-0.1Sc-Ti alloy is accurate detection of bending in the temperature accompanied by a shape memory effect when heated range of the second MT a bigger load of 600 g was at a rate of about 20ºC min–1. It has recently been used for the same sample. A partial bending curve reported that the ZrIr equiatomic compound with for the interval of the second transformation is shown a temperature of martensitic transformation about in Figure 6(b). A partial bending curve for the first 740ºC reveals a partial shape recovery, ~75%, only on a transformation for another sample with parameters rapid heating of the sample (~100ºC sec–1) (14). 0.9 × 1.4 × 8 mm and a load of 250 g is shown in Figure 6(c). Applying a load greater than 250 g was Dilatometry not possible, due to expected plastic deformation at The results of dilatometric analysis of alloy with 0.1 at% 850ºC when the alloy is in a high temperature phase Sc agree with those of the electrical resistance and with a cubic crystal structure. thermomechanical tests. There are two inflections in

–P1 0.5

0.4 (a)

0.3 Height, mm 0.2

11 (b) MMss

M2 2 Ms s A 0.1 –P2

0 +P2 +P1

0.1

–P1 1 Ms 1 (c) Ms

Height, mm +P1

100 200 300 400 500 600 700 800 900 Temperature, ºC

Fig. 6. Thermomechanical curve of the 50Rh-0.1Sc–Ti alloy: (a) full bending curve; (b) partial bending curve in the region of the second MT; (c) partial bending curve in the region of the first MT; A – area of deformation martensite prior to the first transformation; and B – a two-way shape memory effect

the dilatometric curve, corresponding to the beginning was packed in an envelope made of stainless steel. of the first (A) and second (B) MTs (Figure 7). A Initial package thickness was 2.3 mm. As a result of sharp change in the length of the sample in a narrow 15 cycles of rolling and heating to 950ºC the thickness temperature range related to the first MT was observed of the package decreased to 0.8 mm. The obtained as an abnormal effect on the electrical resistance sample was 0.18 mm thick and 17 mm long. From the curve at the same temperature for the alloys containing experiment it follows that at 950ºC this alloy is ductile more scandium (Figures 2(a) and 2(b)). whereas at 20ºC it is not. Therefore, parts of heat sensitive items can be manufactured by hot rolling Ductility and extrusion. Not all alloys with a shape memory It was noticed that the Rh-Sc-Ti alloys are only slightly effect can be used for high-temperature materials; from oxidised at 20ºC–950ºC and are quite ductile at 900ºC. observations on the mechanical properties of 50 at% A sample of the alloy with 0.1 at% Sc having a section Rh-0.1 at% Sc-Ti alloy, it can be assumed that material of 0.5 × 1.3 mm was bent at an angle of 90º, then was based on it would not meet difficulties in processing. straightened and bent again in the opposite direction by 90º at 900ºC. It remained undestroyed and without Conclusion any sign of cracks. In order to elucidate the degree of The transformation characteristics and recovery plasticity of the alloy, hot rolling of a 0.4 × 6 × 2 mm behaviour of ScRh-TiRh alloys have been studied. sample cut from ingot was performed. The sample The results show that ScRh-TiRh alloys containing

0.15 A

0.10

Sample length, mm 0.05

100 200 300 400 500 600 700 800 900 Temperature, ºC

Fig. 7. Dilatometric curve of the 50Rh-0.1Sc-Ti alloy: A, B – effects related to transformation in the alloy (see text for explanation)

0–3.5 at% Sc undergo two high-temperature martensitic 4 T. D. Shtepa, “Interaction of Titanium with Platinum 1 2 transformations: Ms ≤ 750ºC and Ms ≤ 340ºC; while Group Metals”. It was placed in collected articles alloys with 16.7 at% and 21 at% Sc reveal only one (compendium) titled “Physical chemistry of condense MT. Both transformations are responsible for the phases, superhard materials and their interface”, Naukova Dumka, Kiev, 1975, pp. 175–191 shape memory effect in these alloys. The temperature 5 J. Balun and G. Inden, Intermetallics, 2006, 14, (3), 260 of martensitic transformations in ScRh-TiRh alloys depends on the scandium content and decreases on 6 E. L. Semenova, V. M. Petyukh and Yu. V. Kudryavtsev, J. Alloys Compd., 1995, 230, (2), 115 substitution of scandium for titanium. The martensitic 7 H. Okamoto, J. Phase Equilib., 2000, 21, (4), 413 transformation temperatures of ScRh-TiRh alloys 8 E. L. Semenova and Yu. V. Kudriavtsev, “The Effect of demonstrate low hysteresis. Transformations occurring Scandium on Martensitic Transformation in TiNi and in TiRh and ScRh-TiRh alloys are first order. TiRh binary TiRh” in the Programme and Abstracts of the 13th and 50 at% Rh-Sc-Ti ternary alloys can display 100% International Conference on Solid Compounds of shape memory effect in two temperature ranges up to Transition Elements (SCTE 2000), Stresa, Italy, 4th–7th 850ºC; TiRh and ScRh-TiRh alloys also exhibit a two- April, 2000, P-C42 way shape memory effect. 9 O. L. Semenova, Yu. V. Kudriavtsev, V. M. Petyuch and All characteristics of ScRh-TiRh alloys observed in O. S. Fomichov, Powder Metall. Metal Ceramics, in press the study make them good candidate materials for 10 V. V. Martynov and L. G. Khandros, Phys. Met. Metallog., 1975, 39, (5), 1037 high-temperature shape memory alloys. Both TiRh and 50 at% Rh-Sc-Ti alloys display the unusual features of 11 V. G. Pushin, V. V. Kondrat'ev and V. N. Khachin, Izv. Vyssh. Fiz., 1985, 28, (5), 5 continuity of the deformation process on cooling and 12 K. Otsuka and X. Ren, Mater. Sci. Eng. A, 1999, continuity of shape recovery process when heated in 273–275, (12), 89 a temperature range from 20ºC to 750ºC, which might 13 V. N. Khachin, Izv. Vyssh. Fiz., 1985, 28, (5), 88 be due to two stages of transformation. The large 14 Yu.V. Kudryavtsev and O. L. Semenova, Powder Metall. range of shape memory effect observed in this work Metal Ceramics, 2011, 50, (7–8), 471 suggests that these alloys may be useful in different temperature-regulating elements that are designed to The Authors work in a wide temperature range. Yurii Kudriavtsev is a scientific researcher at This article presents the results of a preliminary the Kurdyumov Institute of Metals Physics of investigation of the unusual properties of Rh-Sc-Ti alloys, NASU. His interests are in the field of physics metals and martensitic transformation. He in particular with respect to their thermomechanical is involved in the investigation of shape behaviour. Further experimental work is required in memory effect at high temperatures of platinum-based alloys. order to confirm the effects observed. It is hoped that the article will be of interest to other scientists and will stimulate cooperation. Elena Semenova is a senior researcher at the I. N. Frantsevich Institute for Problems of Materials Science of NASU . She has been working there since graduating from Kiev References State University. Her key field of research has 1 A. Raman and K. Schubert, Z. Metallkd., 1964, 55, been focused on the interaction in binary (11), 704 and multicomponent systems formed by transition metals (including platinum group 2 P. Rogl, Atomic Energy Rev., 1983, Special Issue 9, 201 metals) and the equiatomic phases of which undergo martensitic transformation. Physical 3 S. S. Yi, B. H. Chen and H. F. Franzen, J. Less Common and chemical properties of the alloys have Met., 1988, 143, (1–2), 243 been investigated for characterisation.

EuropaCat XI

Highlights of catalysis by pgms and base metals from the biennial congress

http://dx.doi.org/10.1595/147106714X676244 http://www.platinummetalsreview.com/

Reviewed by Silvia Alcove Clave, Francesco 1. Introduction Dolci, Peter R. Ellis* and Cristina Estruch Bosch The 11th EuropaCat meeting was hosted in Lyon, Johnson Matthey Technology Centre, Blount’s Court, France, on the 20th anniversary of the fi rst meeting held Sonning Common, Reading RG4 9NH, UK in 1993 in Montpelier – bringing it back to its origin in *Email: [email protected] France. The event was a large gathering of delegates in many disciplines of catalysis from across Europe and further afi eld. The schedule was busy, with plenary lectures and keynote talks from invited speakers, oral and poster presentations and a full programme of discussion sessions where the presentations were brief and discussion amongst the delegates was promoted. Of particular note was the high quality of the six plenary lectures. These are discussed in more detail below, followed by selected highlights on the themes of emissions control, biomass conversion, process chemistry and catalyst synthesis. Further information on the EuropaCat XI conference, including details of the scientifi c programme and biographies of the invited speakers, can be found on the conference website (1).

2. Plenary Lectures Each session began with a plenary lecture given by a notable professor in the fi eld of catalysis. The fi rst presenter was Bert Weckhuysen (Utrecht University, The Netherlands) who provided an overview of in situ characterisation to understand issues such as catalyst coking and catalyst poisoning in fl uid catalytic cracking and methanol-to-olefi n processes. Combinations of techniques such as ultraviolet- visible (UV-Vis) microscopy, fl uorescence, hard micro- X-ray diffraction, time-of-fl ight-secondary ion mass spectrometry (ToF-SIMS) and X-ray absorption near edge structure (XANES) spectroscopy using different energies managed to evidence three-dimensional (3D) dis-homogeneities in the elemental distribution of samples (zeolites in particular) and correlate them with the specifi c reactivity of different regions on the catalyst surface. Ferdi Schüth (Max-Planck-Institut f. Kohlenforschung, Germany) was invited to present different preparation routes for controlled nanoparticle systems. He proposed the introduction of a size-controlled gold

nanoparticle in a zirconium dioxide (ZrO2) system

starting from a colloidal suspension with the aim of CO2 formation are some of the issues faced when preventing the sintering of catalytically active particles. working with these reactions. The speaker presented This has been extended to the formation of alloys several examples during his talk. When considering

(platinum, ruthenium) coated onto carbon shells for CH4 pyrolysis the C2–C10 yield is limited by both fuel cell catalysts and CoPt for biomass conversion. thermodynamics and polynuclear aromatic chain

A second interesting idea was the use of ball milling growth. The C11+ formation can be controlled by using to promote catalytic reactions. For example, carbon catalytic materials, such as Mo/H-ZSM5, that can stop monoxide could be oxidised over cobalt(II,III) oxide chain growth. The thermodynamics and kinetics for this

(Co3O4) in a ball mill, but the reaction stopped when reaction can be improved by removing the hydrogen. the mill was switched off. The milling was thought Indirect paths can be used to reduce the conversion to generate transient sites on the Co3O4 which were of CH4 to the undesired CO2 or C. The process will highly active. include chemically protected intermediates which are Marc Fontecave (Collège de France, France) gave less reactive than methane. For example, synthesis gas a talk on recently developed Co and nickel-based is a thermodynamically protected form of activated catalysts for the (photo)catalytic production and methane. This is quite reactive and can be converted oxidation of hydrogen. The insertion of Co into to a broad range of hydrocarbons. iron(III) oxide/tungsten oxide (Fe2O3/WO3) catalysts The fi nal plenary lecture, given by Dmitry Murzin for the (photo)anode was suggested. Co3O4 has been (Åbo Akademi University, Finland) was a fascinating shown to have good storage properties but has no insight into the synthesis of pharmaceutical materials effect on H2 production. Fe-Ni compounds and some from naturally-occurring biomolecules. On the face Co complexes are currently used for the production of it, this may seem like an unpromising avenue, of H2. More recently, Ni complexes have been grafted but as both classes of molecule contain high levels onto carbon nanotubes (CNTs) and deposited on of functionality, signifi cant progress can be made an electrode. They have also been modifi ed to be by appropriate selection of the starting material resistant to CO; however, it has been suggested that a and effi cient use of catalytic functional group diimine-dioxime Co complex binding system may be transformations. A good example of material selection more robust under acidic conditions. At the moment, was the lignan 7-hydroxymatairesinol (Figure 1(a)). other metals such as Ru and iridium are under The knots found in wood are particularly rich in investigation in the photosynthesis fi eld. such lignans and since they cannot be processed During the Michel Boudart Award lecture, Jens into paper due to their hardness they are essentially Norskov (Stanford University, USA) gave an interesting a low value waste material. 7-hydroxymatairesinol overview on the possibilities offered by computational can be converted into a number of useful products, modelling applied to catalysis. The speaker showed including 7-oxomatairesinol (Figure 1(b)) which how linking catalytic activity to the electronic is has potential anticarcinogenic and antioxidative structure and chemical composition of a material properties. This conversion was achieved using an is feasible if the problem is approached correctly. Au-catalysed selective oxidation reaction. In these The main message of the presentation lay in the reactions, achieving excellent selectivity to the desired importance of fi nding the appropriate descriptors for product is critical to applications in pharmaceutical catalytic activity and selectivity. Once this information materials. is available, the design and optimisation of a process becomes possible, and catalyst and process selections 3. Emission Control Technologies can be carried out on a more rational and effective The catalytic conversion of environmentally hazardous basis. Examples such as ammonia synthesis were pollutants in automobile exhausts was a thoroughly provided and illustrated these concepts well. debated topic in the conference and a wide range of Enrique Iglesia (University of California, USA) gave research studies were presented, including theoretical the François Gault lecture in which he discussed the modelling of materials or processes, optimisation challenges presented by the conversion of molecules of the current state of the art and new ideas and without a C–C bond, such as methane, methanol concepts. Those presentations presenting original and dimethyl ether. Overcoming thermodynamics, ideas and newly achieved insight can have a more the use of inexpensive oxidants, protecting species general appeal and have been selectively covered in with weaker C–H bonds, inhibition of carbon and this report.

(a) (b) O O O O MeO OMe MeO OMe

HO OH HO OH HO O

Fig. 1. The structure of: (a) 7-hydroxymatairesinol; and (b) 7-oxo-matairesinol

3.1 Selective Catalytic Reduction higher thermal stability and improved sulfur dioxide Many advances have been achieved in selective tolerance. catalytic reduction (SCR) technology over the years. The addition of H2 to the gas feed containing nitric oxide Fe- and copper-zeolite and vanadium-based catalyst and NH3 has also been considered over silver/alumina technology is still the most studied for the NH3-SCR catalysts. Stefanie Tamm (Haldor Topsoe) provided a reaction. A keynote speaker in this area was Isabella global kinetic model for this reaction. Another type of

Nova (LCCP Politecnico di Milano, Italy), who SCR system uses hydrocarbons (HC) instead of NH3 proposed a detailed and universal SCR mechanism as a reductant, although at the moment these systems over the standard commercial catalysts (Figure 2) cannot offer the performance of NH3-SCR systems. (2). Several speakers provided information on the Asima Sultana (Advanced Industrial Science and reaction mechanism and metal active sites in Cu- Technology (AIST), Japan) showed that by adding NH3 zeolites. Florian Göltl (Université de Lyon, France) into a HC SCR over Ag/Al2O3 catalyst nitrogen oxides suggested a new type of active site for Cu in chabazite conversion could be improved. structures (SSZ-13) by modelling the adsorption of CO to a Cu(I) site. Janos Szanyi (Pacifi c Northwest 3.2 NOx Storage-Reduction Technology National Laboratory, USA) also focused his studies on NOx can be removed from a lean gas stream by Cu-SSZ13 and proposed that the formation of Cu-nitrosyl chemical adsorption onto a catalyst and subsequently adsorbed onto SSZ-13 could be the key intermediate reduced to N2. Several materials were proposed for for the NH3-SCR reaction. Regarding V-based catalysts, NOx storage during the conference. The commercial a ceria loaded Sb-V/TiO2 catalyst was mentioned by Pt-Ba/Al2O3 catalyst was mentioned by two speakers. Heon Phil Ha (KIST, South Korea). The addition of Laura Righini (Politecnico di Milano) proposed a

CeO2 to the Sb-V/TiO2 catalyst resulted in superior mechanism for the reduction by NH3 of NOx stored catalytic activity over a wide range of temperatures, on this catalyst, suggesting that the release of stored

Fig. 2. A NO NO2 N2O + 2H2O proposed + NH4NO2 NH4 mechanistic + model for NH4 standard and fast NH -SCR – – N2 + 2H2O 3 NH4NO3 NO3 NO2 reaction (2, 3)

+ O2 NH4 NH3 + HNO3 NO

2NO2

NOx is the rate determining step for the reduction of oxo-clusters for methane oxidation. The crucial nitrates. Beñat Pereda-Ayo (University of the Basque parameters of the proposed model are the C–H bond Country, Spain) provided evidence that the addition activation energy, the highest occupied molecular of Ce improves the NOx storage capabilities of orbital-lowest unoccupied molecular orbital (HOMO-

Pt-Ba/Al2O3. The optimum Ce loading was found to be LUMO) gap of the surface transition metal oxo- 5%. Manganese and Co-based lanthanum perovskite clusters and the properties of the Lewis basic support doped with Pd were also presented as optimum (gauged by the optical basicity, ), accommodating catalysts with high NOx storage capacity and good the detached proton. By optimising different S-uptake/release properties. Merve Do˘gaç and parameters at the same time the authors managed Emrah Özensoy (Bilkent University, Turkey) proposed to show how catalytic activity can be improved. A lanthanum manganite (LaMnO3) perovskite as the very interesting concept for obtaining an active and best example, with a higher surface area compared to ageing-resistant CH4 oxidation catalyst was presented a Co-based equivalent. by Paolo Fornasiero (University of Trieste, Italy). Core-

shell structures of Pd encapsulated in CeO2 appear 3.3 Soot Oxidation to stabilise the active phase of the catalyst, not only Marzia Casanova (University of Udine, Italy) preventing agglomeration of palladium(II) oxide introduced Fe/V catalysts supported on ceria-zirconia (PdO) particles during the catalytic reaction, but also

(Ce0.75Zr0.25O2) for simultaneous activity for both preventing PdO from being transformed to Pd at its SCR and soot oxidation. Obtaining a good activity for usual transition temperature. The authors speculated both processes remains challenging and further work also on the role played by hydroxyl groups on the seems to be needed before this concept can acquire loss of catalytic performance and how regeneration commercial viability. Michela Klots (Centre National strategies impact the recovery of catalytic activity. de la Recherche Scientifi que (CNRS), Saint-Gobain, France) and Emil Obeid (Institut de Recherches sur 4. Biomass Processing la Catalyse et L’Environnement de Lyon (IRCELYON), In recent years interest in the conversion of biomass France) showed how the design of a soot oxidation into biofuels and biochemicals has increased due catalyst can be improved by exploiting knowledge of to growing demand for energy and more stringent oxygen and electronic diffusion processes commonly environmental requirements. This interest was refl ected used in designing solid state fuel cells. throughout the conference. In the area of biofuels, the By using a theoretical modelling approach, conversion of glycerol to form hydrogen by aqueous Andrzej Kotarba (Jagiellonian University, Poland) phase reforming (APR) was discussed by Pedro Arias explored the key parameters of the soot oxidation (University of Basque Country). His group compared process for a platinum group metal (pgm)-free soot the activity of Pt/ɣ-Al2O3, Ni/ɣ-Al2O3 and PtNi/ɣ-Al2O3 oxidation catalyst. The interaction between the soot catalysts prepared by two different methods: sol-gel grains and the oxide catalyst, topology of the soot and impregnation. The catalyst prepared by the sol-gel molecular framework and infl uence of potassium method initially showed a higher H2 production but doping on the work function were investigated. For subsequent deactivation reduced the levels to the K-Fe-O systems a strong correlation was observed same as those of the impregnated catalysts. For these between the catalytic activity and the work function. catalysts the ɣ-Al2O3 was converted into boehmite The infl uence of potassium on the nanostructure of (ɣ-AlOOH) during APR, resulting in Ni sintering. The iron oxide, leading to tunnelled and layered forms, stability of the catalyst is a well-known problem in APR together with surface decoration by CeO2 helped to and the use of other supports such as carbon may be lower the work function, resulting in a substantial a solution. Another example of hydrogen production increase in catalytic activity. It was proposed that was delivered by Dimitri Bulushev (University of enhanced electron availability is benefi cial for the Limerick, Ireland). He explained that the production generation of surface reactive oxygen species that of hydrogen from biomass-derived formic acid at low initialise the combustion process. temperatures (60ºC) could be improved by doping the Pd/C catalyst with K ions. 3.4 Methane Oxidation Several talks focused on the production Zbigniew Sojka (Jagiellonian University) presented of biochemicals. The production of 1,2- and a model for rationalising the activity of deposited 1,3-propanediol from glycerol using a Pt/WO3/Al2O3

catalyst was examined by Sara Garcia Fernandez Processing syngas to higher olefi ns was also (University of Basque Country). The catalyst was discussed by James Spivey (Louisiana State University, prepared by sequential impregnation of Al2O3. The USA). He used a CuCo catalyst and found through Lewis/Bronsted acidity could be tuned by the amount modelling that a bimetallic active site gave the best of WO3. An increase of Lewis sites decreased the performance. Ard Koeken (Utrecht University) used an selectivity towards 1,2-propanediol. The effect of Pt Fe catalyst for the same reaction; typically for Fe-based was also studied, showing an increase in activity with FT, iron carbide was thought to be the active site. increasing metal content. The formation of iron carbide was measured using The hydrodeoxygenation of biomass derived ketones a tapered element oscillating microbalance. The was presented by several groups. Ivan Kozhevnikov formation of carbon phases was also observed when (University of Liverpool, UK) showed high conversion the catalyst was exposed to 20 bar syngas at 350ºC, of methyl isobutyl ketone (MIBK) to 2-methylpentane although this could be supressed by increasing the over Pt/H-ZSM-5 at 200ºC. At lower temperatures the use H2/CO ratio from 1 to 2. of Pt loaded on acidic heteropoly salt Cs2.5H0.5PW12O40 Conversion of syngas to alcohols using Pd and Rh catalyst for the hydrogenation of MIBK and diisobutyl catalysts was presented by Shuichi Naito (Kanagawa ketone to the corresponding alkanes gave yields of University, Japan). A Pd/CeO2 catalyst gave methanol 97%–99%. This catalyst was stable for over 16 h and and HCs, whilst Rh/CeO2 gave mostly hydrocarbons. little coke formation was observed. A bifunctional Increasing Rh particle size increased hydrocarbon metal-acid catalysed pathway was identifi ed for these selectivity. Addition of lithium to either system catalysts. The effect of Pd and Pt particle sizes on the decreased hydrocarbon formation and increased hydrodeoxygenation of 5-nonanone to form n-nonane selectivity to oxygenates. and 5-nonanol was investigated by Irina Simakova (Boreskov Institute of Catalysis, Russia). The catalysts 5.2 Selective Hydrogenation studied were Pd/ZrO2 and Pt/ZrO2. An increase in Selective hydrogenation was a major theme at the selectivity to n-nonane was observed with decreasing conference. One of the main feedstocks investigated particle size. was alkynes which can be selectively hydrogenated to alkenes. One talk of particular interest by Daniel 5. Process Chemistry Lamey (Ecole Polytechnique Fédérale de Lausanne 5.1 Syngas Processing (EPFL), Switzerland) described the use of supported Freek Kapteijn (Delft University of Technology, The Pd nanoparticles in the hydrogenation of acetylene Netherlands) took an engineering approach to the to ethane in the presence of excess ethane. The Fischer-Tropsch (FT) reaction, describing the effects nanoparticles were made by reduction of Pd salts in the of diffusion and H2:CO ratio. CO diffuses more slowly presence of polymer stabilisers. Catalyst testing showed than hydrogen and so the ‘real’ H2:CO ratio in catalyst that the larger particles (10 nm) were the most active, pores could be much higher than that supplied to the whilst the smallest particles (2 nm) were the most reaction. He also reported a Co/ZSM-5 catalyst which selective to ethane and gave the lowest amounts of the maximised the yield of the petroleum fraction made by-product green oil. The best catalyst described was a and decreased C21+ to almost zero. The CH4 selectivity, 4 nm nanoparticle stabilised with polyvinylpyrrolidone however, increased from 6% to 15% when compared (PVP) and using a polyethyleneimine polymer to block with a similar Co/SiO2 catalyst, although the Co/ZSM-5 unselective sites on the catalyst. catalyst was more active. Ye Wang (Xiamen University, Gianvito Vilé (Eidgenössische Technische China) used Ru/zeolite catalysts for the same reaction. Hochschule (ETH) Zürich, Switzerland) reported silver-

Ru nanoparticles gave lower selectivity to CH4 and C2–4 based catalysts for propyne hydrogenation, supported than Co and using a wide pore zeolite support gave on titania or silica. Catalytic measurements suggested less secondary cracking to low Cn products due to a that splitting H2 was the rate limiting step on these reduced residence time. A Co/TiO2-SiC catalyst was catalysts – as the hydrogen concentration increased, described by Y. Liu (University of Strasbourg, France). the rate increased. However density functional theory

This performed well, with C5+ selectivity at 90% and (DFT) calculations suggested a lower energy route 50% conversion at a gas hourly space velocity (GHSV) which reacted molecular hydrogen directly with the of 2850 h−1. alkyne (Equation (i)).

hydrogenation liquid-phase reactions, respectively, more complex HC CH H2C CH2 (i) substrates were also investigated. For example, Stefania Albonetti (Università di Bologna, Italy) and The selective hydrogenation of dimethyl oxalate to Florentina Neatu (University of Bucharest, Romania) ethylene glycol was reported using Cu/SiO2 catalysts both reported the oxidation of hydroxymethylfurfural by Y. Yuan (Xiamen University, China). The catalyst was to furandicarboxylic acid. Hydroxymethylfurfural reduced at 350ºC prior to reaction, leading to Cu(0) is of interest as it can be readily synthesised from and Cu(I) active sites. Decoration of the catalyst with cellulose (Figure 3). Albonetti used Au and CuAu low levels of Au increased the conversion and the catalysts whilst Neatu used CuMn and FeMn, selectivity to ethylene glycol. Meanwhile P. Chen (Ruhr illustrating the range of materials which are active University, Germany) investigated CNTs doped with oxidation catalysts. oxygen or nitrogen as supports for the hydrogenation of olefi ns. Addition of Pt or Pd gave an active catalyst; 6. Catalyst Synthesis X-ray photoelectron spectroscopy (XPS) showed that A number of talks were focussed on materials synthesis the N- or O-dopant had an electronic impact on the rather than understanding of reactions. The main precious metal. catalyst preparation technologies – impregnation, deposition and so on – were well-represented. The 5.3 Oxidation Catalysis synthesis of catalysts using pre-formed nanoparticles Again, a wide range of substrates, processing methods is growing in popularity, as parameters such as particle and catalysts were described for selective oxidation. size and shape and the addition of second metals can Selective oxidation attracted much more attention be controlled. than total oxidation, despite the relevance of the latter One talk which stood out was by Gonzalo Prieto to pollution control. As is often the case in oxidation, (Utrecht University). He described a Cu/SBA-15 a wide range of materials were reported, including material which was prepared by impregnation pgms, Au, base metals and combinations of two or and calcined in two ways. When calcined under more of the above. Au catalysts were inevitably well N2, the CuO particles were well dispersed through represented. This was especially true of Au/TiO2 the support, whilst calcination using a 2% NO/N2 which has taken the role of a benchmark oxidation atmosphere led to only some of the support’s channels catalyst, amongst the academic community if not the containing the particles. The catalyst calcined under industrial one. Bimetallic catalysts containing Au were nitrogen resisted sintering as the particles were also popular choices, especially PdAu and CuAu on a further apart (Figure 4). The work has been reported range of supports. in full elsewhere (4). One notable feature of the oxidation work presented Sintering control was also discussed by Ferdi was the range of substrates being investigated. Schüth in his plenary lecture. He reported a multistep Whilst the oxidation of CO and of benzyl alcohol synthesis of Au nanoparticles captured in zirconia could be considered as standard gas-phase and shells (Figure 5). The shells were porous enough to

Fig. 3. The oxidation of HO2CCO2H hydroxymethylfurfural to HO O oxidation furandicarboxylic acid

Hydroxymethylfurfural Furandicarboxylic acid

(a) (b) Fig. 4. A Cu/SBA-15 material was calcined in two ways: (a) NO/N2 calcined which sintered easily; and (b) N2 calcined which resisted sintering

Si Source Zr Source HF etching

Au nanoparticle SiO2 coated ZrO2 Shell Au in ZrO2 Shell

Fig. 5. The multistep synthesis of Au nanoparticles captured in ZrO2 shells allow reagents and product to diffuse in and out, but The next EuropaCat conference (EuropaCat XII) the particles were trapped and therefore could not will take place in Kazan, Russia, in 2015, reaching sinter. A similar approach was described by Paolo the geographical boundaries between Europe Fornasiero, as discussed in Section 3.4. and Asia and hopefully again bringing together a comprehensive and stimulating programme.

7. Summary Overall this EuropaCat conference was very well References attended and managed in a very effi cient way, despite 1 XIth European Congress on Catalysis: www europacatlyon2013.fr (Accessed on 6th December the volume of participants. The different parallel 2013) sessions and discussion symposia (up to seven 2 A. Grossale, I. Nova, E. Tronconi, D. Chatterjee and parallel sessions in the same time slot) covered almost M. Weibel, J. Catal., 2008, 256, (2), 312 all possible topics, established and new, relevant 3 I. Nova, C. Ciardelli, E. Tronconi, D. Chatterjee and for the catalysis community. As a general feeling M. Weibel, AIChE J., 2009, 55, (6), 1514 heterogeneous catalysis received more attention 4 G. Prieto, J. Zeˇcevi´c, H. Friedrich, K. P. de Jong and than homogeneous catalysis, but both were covered. P. E. de Jongh, Nature Materials, 2013, 12, (1), 34

The Reviewers

Silvia Alcove obtained her Francesco Dolci obtained Peter R. Ellis gained his Cristina Estruch Bosch studied BSc from Rovira i Virgily a BSc and a PhD from the BSc and PhD from Durham Chemistry followed by a University, Spain. She University of Turin, Italy. He University, UK. Following Masters in Catalysis at the joined the Emission Control then moved to The Institute post-doctoral placements in Rovira i Virgili University . She Technologies department of Nanotechnology in Reading University, UK, and carried out her master’s ﬁ nal at Johnson Matthey Karlsruhe, Germany, and to Queens University Belfast, project during an internship Technology Centre, Sonning the Joint Research Centre of UK, he joined Johnson at Johnson Matthey Common, UK, in 2009. , the European Commission Matthey in 2001. His current Technology Centre, studying She is currently undertaking in Petten, The Netherlands research interests are liquid phase methane an Engineering Doctorate for working on solid state heterogeneous catalysts for a oxidation. After that, she (EngD) in collaboration with hydrogen storage materials. range of processes including became a Johnson Matthey Nottingham University. Her In August 2012 he joined the Fischer-Tropsch, direct employee and continued research project mainly Emission Control Research hydrogen peroxide synthesis to work in heterogeneous consists of improving the department in Johnson and selective oxidation catalysis. She then started NH3-SCR catalysis technology Matthey, working mainly and also the utilisation of a PhD in collaboration with for high NOx reduction and on three-way catalysis pre-formed nanoparticles in Ghent University, Belgium, better mercury oxidation in development. heterogeneous catalysis. within a European project in power plant industries. which Johnson Matthey is a project partner. She is now working on new projects involving biomass conversion and hydrogenation whilst writing up her thesis.

The Discoverers of the Isotopes of the Platinum Group of Elements: Update 2014

A resolution of the discovery circumstances of 195Os plus new isotopes found for Ru

http://dx.doi.org/10.1595/147106713X675778 http://www.platinummetalsreview.com/

Further to a previous update (1), a new investigation of (7) normalised to a value of 2 ± 1.7 h. The details the discovery circumstances of 195Os by Juan Flegen surrounding the discoveries of 195Os isotopes are (2) has shown that Baró and Rey almost certainly summarised in Table I. In addition the new isotopes discovered this isotope in 1957 (3, 4). A previous 85Ru and 86Ru have been discovered at the RIKEN Nishina suggestion that they had only observed the isotope Center in Japan (8) with the discovery circumstances 81Rb was due to a misunderstanding which was only summarised in Table II. Table III shows the total number resolved by a critical assessment of the papers of Rey of isotopes to date for each platinum group element. and Baró by Birch et al. (5). In addition Reed et al. (6) have identifi ed an isomer of 195Os by determining JOHN W. ARBLASTER the half-life on the bare nucleus, Os76+. They obtained Wombourne, West Midlands, UK +154 32 –16 m for the half-life which NUBASE 2012 Email: [email protected]

Table I The Discoverers of the 195Os Isotopes

Mass number Half-life Decay modes Year of discovery Discoverers References 195 6.5 min –? 1957 Baró and Rey 3, 4 195m 2 h –?, IT? 2012 Reed et al. 6

Table II New Isotopes of Ruthenium

Mass number Half-life Decay modes Year of discovery Discoverers References 85 ps EC + +? 2013 Suzuki et al.8 86 ps EC + +? 2013 Suzuki et al.8 ps: Particle stable (resistant to proton and neutron decay)

EC: Orbital electron capture in which the nucleus captures an extranuclear (orbital) electron which reacts with a proton to form a neutron and a neutrino, so that the mass number of the daughter nucleus remains the same but the atomic number decreases by one

+: Beta or proton decay for nuclear deﬁ cient nuclides is the emission of a positron (and a neutrino) as a proton in the nucleus decays to a neutron. As with EC the mass number of the daughter nuclide remains the same but the atomic number decreases by one. However this decay mode cannot occur unless the decay energy exceeds 1.022 MeV (twice the electron mass in energy units)

Table III Total Number of Isotopes and Mass Ranges Known for Each Platinum Group Element to 2014

Element Number of known isotopes Known mass number ranges Ru 40 85–124 Rh 38 89–126 Pd 38 91–128 Os 43 161–203 Ir 42 164–205 Pt 44 166–209

References

1 J. W. Arblaster, Platinum Metals Rev., 2012, 56, (4), 271 Blachot and M. MacCormick, Chinese Phys. C, 2012, 36, 2 J. Flegen private communication to J. W. Arblaster, (12), 1157 June 2013 8 H. Suzuki, T. Kubo, N. Fukuda, N. Inabe, D. Kameda, H. Takeda, K. Yoshida, K. Kusaka, Y. Yanagisawa, M. Ohtake, 3 G. Baró and P. Rey, Z. Naturforsch., 1957, 129, (6), 520 H. Sato, Y. Shimizu, H. Baba, M. Kurokawa, T. Ohnishi, 4 P. Rey and G. Baró, Publs. Com. Nucl. Energia Atòmica K. Tanaka, O. B. Tarasov, D. Bazin, D. J. Morrissey, B. M. (Buenos Aires) Ser. Quim., 1957, 1, (10), 115 Sherrill, K. Ieki, D. Murai, N. Iwasa, A. Chiba, Y. Ohkoda, 5 M. Birch, J. Flegenheimer, Z. Schaedig, B. Singh and M. E. Ideguchi, S. Go, R. Yokoyama, T. Fujii, D. Nishimura, Thoennessen, Preprint arXiv: 1312.3985v1 [nucl-ex], H. Nishibata, S. Momota, M. Lewitowicz, G. DeFrance, 14th December, 2013 I. Celikovic and K. Steiger, Preprint arXiv:1310.5945v1 [nucl-ex], 22nd October, 2013 6 M. W. Reed, P. M. Walker, I. J. Cullen, Yu. A. Litvinov, S. Shubina, G. D. Dracoulis, K. Blaum, F. Bosch, C. Brandau, J. J. Carroll, D. M. Cullen, A. Y. Deo, B. The Author Detwiler, C. Dimopoulou, G. X. Dong, F. Farinon, H. John W. Arblaster is Geissel, E. Haettner, M. Heil, R. S. Kempley, R. Knöbel, interested in the history of C. Kozhuharov, J. Kurcewicz, N. Kuzminchuk, S. Litvinov, science and the evaluation of the thermodynamic and Z. Liu, R. Mao, C. Nociforo, F. Nolden, W. R. Pla, Zs. crystallographic properties of Podolyak, A. Prochazka, C. Scheidenberger, M. Steck, the elements. Now retired, he previously worked as Th. Stöhlker, B. Sun, T. P. D. Swan, G. Trees, H. Weick, a metallurgical chemist in N. Winckler, M. Winkler, P. J. Woods, F. R. Xu and T. a number of commercial Yamaguchi, Phys. Rev. C, 2012, 86, (5), 054321 laboratories and was involved in the analysis of a wide range of 7 G. Audi, F. G. Kondev, M. Wang, B. Pfeiffer, X. Sun, J. ferrous and non-ferrous alloys.

PGMs IN THE LAB Platinum Group Metals in Polyoxometalates

Johnson Matthey and Alfa Aesar support new platinum group metals research

Here another researcher whose work has benefited from the support of Johnson Matthey and Alfa About the Researcher Aesar, A Johnson Matthey Company, is profiled. Ulrich Kortz is a Professor of Chemistry at Jacobs University in Bremen, Germany, and he is interested in the synthesis and characterisation of noble metal- containing polyoxometalates.

About the Research Polyoxometalates (POMs) are a large class of discrete, soluble metal-oxo anions of early transition metals in high oxidation states, such as tungsten(VI) or molybdenum(VI). Due to a unique combination of properties, such as thermal and oxidative stability, Professor Ulrich Kortz tunability of acidity and redox activity, solubility * Name: Ulrich Kortz in various media, and ability to undergo multistep * Position: Professor of Chemistry multi-electron transfers without structural changes, * Department: School of Engineering and POMs keep attracting more and more attention in Science different areas of fundamental and industrial science, * University: Jacobs University in particular in homogeneous and heterogeneous catalysis. * Street: Campus Ring 1 Kortz’s group are world leaders in the synthesis and * City: Bremen characterisation of noble metal-containing polyanions. * Post or Zip Code: 28759 They prepared the fi rst example of a Pt(IV)-containing * Country: Germany IV 5– polyoxovanadate, [H2Pt V9O28] by a facile synthetic * Email Address: [email protected] procedure, using the Pt(IV) precursor H Pt(OH) . The 2 6 * Website: http://www.jacobs-university.de/ polyanion [H PtIVV O ]5– was characterised in the 2 9 28 ses/ukortz solid state by X-ray diffraction (XRD) and in solution by 195Pt and 51V NMR spectroscopy. Their research also includes the fi rst example II V 8– of a Pd(II)-containing heteropolyoxometalate, [Pd 13As 8O34(OH)6] , which has the shape and III 9– [Cs2Na(H2O)10Pd3(-Sb W9O33)2] which consists dimensions of a molecular nanocube (Figure 2). of two (-SbW9O33) moieties linked by three square Meanwhile the same group has isolated several other planar-coordinate Pd2+ ions resulting in a sandwich polypalladate derivatives of various shapes, sizes type structure (Figure 1(a)). The central belt is and compositions. Kortz’s group has also pioneered completed by two Cs+ and a Na+ ion which occupy the the class of polyoxoaurates with the discovery III V 8– vacancies between the adjacent Pd centres, resulting of [Au 4As 4O20] . The Se(IV) derivative of this in a polyanion with idealised C2v symmetry (Figure polyanion has also been reported very recently. 1(b)). Polyoxo-noble-metalates can be used in a wide Kortz’s group have pioneered the class range of applications such as catalysis, analysis, of polyoxopalladates with the discovery of medicine, biochemistry and materials science.

(a) (b)

Pd1 Cs3 Cs3’

Pd2 Pd2’

Na1

III 9– Fig. 1. (a) Combined polyhedral/ball-and-stick representation of [Cs2Na(H2O)10Pd3(-Sb W9O33)2] . The WO6 octahedra are shown in red and the balls represent palladium (blue), antimony (green), caesium (yellow), sodium (purple) and water molecules (red); (b) ball-and-stick representation of the central belt of III 9– [Cs2Na(H2O)10Pd3(-Sb W9O33)2] (Reprinted with permission from L.-H. Bi, M. Reicke, U. Kortz, B. Keita, L. Nadjo and R. J. Clark, Inorg. Chem., 2004, 43, (13), 3915. Copyright 2004 American Chemical Society)

J. Carbó, J. M. Poblet, M. S. von Gernler, T. Drewello, P. de Oliveira, B. Keita and U. Kortz, Inorg. Chem., 2012, 51, (24), 13214 N. V. Izarova, M. T. Pope and U. Kortz, Angew. Chem. Int. Ed., 2012, 51, (38), 9492 N. V. Izarova, A. Banerjee and U. Kortz, Inorg. Chem., 2011, 50, (20), 10379 N. V. Izarova, N. Vankova, T. Heine, R. N. Biboum, B. Keita, L. Nadjo and U. Kortz, Angew. Chem. Int. Ed., 2010, 49, (10), 1886 N. V. Izarova, N. Vankova, A. Banerjee, G. B. Jameson, T. Heine, F. Schinle, O. Hampe, U. Kortz, Angew. Chem. Int. Ed., 2010, 49, 7807 E. V. Chubarova and U. Kortz, Exxonmobil Chemical Company, ‘Novel Heteropolyanions with Late Transition Metal Fig. 2. Ball-and-stick representation of Addenda Atoms and Process for their Preparation’, US II V 8– [Pd 13As 8O34(OH)6] . The colour code of the balls is Patent Appl. 2009/0,216,052 as follows: Pd (green), As (blue), O (red). Hydrogens not shown (Copyright 2013 Professor Ulrich Kortz) U. Lee, H.-C. Joo, K.-M. Park, S. S. Mal, U. Kortz, B. Keita and L. Nadjo, Angew. Chem. Int. Ed., 2008, 47, (4), 793

Selected Publications E. V. Chubarova, M. H. Dickman, B. Keita, L. Nadjo, F. Y. Xiang, N. V. Izarova, F. Schinle, O. Hampe, B. Keita and U. Miserque, M. Mifsud, I. W. C. E. Arends and U. Kortz, Kortz, Chem. Commun., 2012, 48, (79), 9849 Angew. Chem. Int. Ed., 2008, 47, (49), 9542 M. Barsukova-Stuckart, N. V. Izarova, R. A. Barrett, Z. Wang, L.-H. Bi, M. Reicke, U. Kortz, B. Keita, L. Nadjo and R. J. Clark, J. van Tol, H. W. Kroto, N. S. Dalal, P. Jiménez-Lozano, J. Inorg. Chem., 2004, 43, (13), 3915

Publications in Brief BOOKS “Computational Catalysis” Edited by A. Asthagiri (Ohio State “A Theoretical Study of Pd-Catalyzed C-C Cross- University, USA) and M. J. Janik Coupling Reactions” (Pennsylvania State University, USA), By M. G. Melchor (Autonomous RSC Catalysis Series No. 14, The Royal University of Barcelona, Spain), Society of Chemistry, Cambridge, UK, Springer Theses, Springer International 276 pages, ISBN: 978-1-84973-451-6, Publishing Switzerland, 2013, 136 £139.99 pages, ISBN: 978-3-319-01490-6, The ultimate goal of computational £90.00, US$129.00 catalysis is the design of a novel The Springer Theses series catalyst entirely from the computer. recognises outstanding PhD This book gives a comprehensive review of the research. This thesis describes how methods and approaches being adopted to push theoretical calculations are used the boundaries of computational catalysis. There are to determine, elucidate and propose mechanisms applied examples to support each method and the for Pd-catalysed C--C cross-coupling reactions. Due editors share over two decades’ experience in this fi eld. to its versatility, broad scope and selectivity under This book is an essential reference to postgraduates mild conditions, the Pd-cross-coupling reaction can and professionals working in the fi eld. be applied in fi elds as diverse as the agrochemical and pharmaceutical industries. The thesis also “Green Diesel Engines: Biodiesel Usage in covers reaction intermediates and transition states Diesel Engines” involved in the Negishi, the copper-free Sonogashira By B. Kegl, M. Kegl and S. Pehan and the asymmetric version of Suzuki-Miyaura (University of Maribor, Slovenia), Series: Lecture Notes in Energy, Vol. coupling. A detailed picture of the associated reaction 12, Springer-Verlag, London, UK, 2013, mechanisms is included. 263 pages, ISBN: 978-1-4471-5324-5, £90.00, €106.99, US$129.00 “Calorimetry and Thermal Methods in Catalysis” Edited by A. Auroux (Institut de Diesel engines are explored in Recherches sur la Catalyse et relation to current research and I’Environnement de Lyon, France), developments, with a focus on Series: Materials Science, Vol. 154, ecology, economy and engine performance. The Springer-Verlag, Berlin, Heidelberg, Germany, 2013, 561 pages, ISBN: 978- most frequently used alternative fuels in diesel 3-642-11953-8, £117.00, €139.09, engines, the properties of various types of biodiesel US$179.00 and the concurrent improvement of diesel engine This book discusses calorimetry characteristics are examined in this book. “Green and thermal analysis methods, Diesel Engines” provides a solid foundation in current alone or linked to other techniques and applied to the research. characterisation of catalysts, supports and adsorbents, “Hydrometallurgy: Fundamentals and and to the study of catalytic reactions in various Applications” domains: air and wastewater treatment, clean and By M. L. Free (University of Utah, USA), renewable energies, refi ning of hydrocarbons, green John Wiley & Sons, Inc, Hoboken, New chemistry, hydrogen production and storage. This book Jersey, USA, 2013, 444 pages, ISBN: aims to fi ll the gap between the basic thermodynamic 978-1-118-23077-0, £90.50, €108.60, and kinetics concepts and the use of experimental US$135.00 techniques such as thermal analysis and calorimetry This book provides a condensed to answer practical questions. The book is suitable as a collection of information that can reference for researchers and engineers, and useful as a be used to improve the effi ciency tutorial for graduate students. and effectiveness with which metals

are extracted, recovered, manufactured and utilised  Reports on portable emission measurement in aqueous media in technically viable and reliable, systems and their application for assessing environmentally responsible and economically gaseous and particulate matter emissions under feasible ways. The book is suitable for students and actual operating conditions and in all transport researchers. modes  Selected fi ndings from exhaust emissions “MWW-Type Titanosilicate: Synthesis, Structural research on engines for various vehicles such as Modifi cation and Catalytic Applications to light-duty, heavy-duty and non-road vehicles. Green Oxidations” By P. Wu, H. Xu, L. Xu, Y. Liu and M. He “Transition Metal-Catalyzed Couplings in (East China Normal University, China), Process Chemistry: Case Studies from the Series: SpringerBriefs in Molecular Pharmaceutical Industry” Science, Springer, Heidelberg, Germany, Edited by J. Magano and J. R. Dunetz 125 pages, ISBN: 978-3-642-39114-9, (Pfi zer Inc, USA), Wiley-VCH Verlag £44.99, €53.49, US$49.99 GmbH & Co KGaA, Weinheim, A comprehensive review of a new Germany, 2013, 401 pages, ISBN: 978- generation of selective oxidation 3-527-33279-3, £115.00, €138.00, US$190.00 titanosilicate catalysts with the The focus of this book is on case MWW topology is provided in this book which gives studies of large scale industrial an overview of the synthesis, structure modifi cation applications, presenting the and catalytic properties of Ti-MWW. Ti-MWW can information and facts that are otherwise hard to fi nd be prepared by direct hydrothermal synthesis with in the current literature. There are contributions by crystallisation-supporting agents, using dual structure authors from Pfi zer, Merck, DSM, Novartis, Amgen and directing agents and a dry gel conversion technique. Astra Zeneca and they use case studies to showcase It can also be post-synthesised through unique project evolution from inception to early and late reversible structure transformation and liquid phase development, including commercial routes where isomorphous substitution. A summary of the structural applicable. At least one transition metal-catalysed conversion of Ti-MWW into materials for processing cross-coupling step is included with each case study. large molecules is provided. Metal removal from the reaction mixtures is also “New Trends in Emission Control in the discussed. There is a small section which covers novel European Union” technologies for cross-coupling with high future By J. Merkisz, J. Pielecha (Poznan potential for applications on a large scale such as metal University of Technology, Poland) removal on a large scale, microwave, fl ow chemistry and S. Radzimirski (Motor Transport and green chemistry. This book is aimed at chemists Institute, Poland), Series: Springer Tracts on Transportation and Traffi c, Vol. working in the pharmaceutical, agrochemical and fi ne 4, Springer International Publishing, chemical industries and also for synthetic chemists Switzerland, 2014, 170 pages, ISBN: working in academia. 978-3-319-02704-3, £90.00, €106.99, US$139.00 Recent changes in the European JOURNALS legislation for exhaust emissions from vehicles are Special Issue: Fuels and Chemicals from discussed in this book. The structure and range of Synthesis Gas: State of the Art applicability of new regulations such as Euro 5 and Catal. Today, 2013, 214, 1–152 Euro 6 for light-duty vehicles and Euro VI for heavy- This special issue is dedicated to duty vehicles are analysed. This comprehensive book a selection of papers presented at also covers: the Syngas Convention “Fuels and  The latest procedures for performing exhaust Chemicals from Synthesis Gas: State emissions tests under both bench and operating of the Art” which was organised conditions by the national DST-NRF Centre of

Excellence in Catalysis (c*change) at the University of Cape Town, South Africa, and run under the auspices of the Catalysis Society of South Africa (CATSA). This convention focused on the generation and uses of synthesis gas for the production of fuels and chemicals. The technologies used for the conversion of synthesis gas into liquid fuels and chemicals are well established but these processes need to be improved to meet the requirements on current and future generations of these technologies. The papers presented at the Syngas Convention were aimed at all areas of synthesis gas conversion.

ChemElectroChem Editor: G. Heydenrych; Wiley-VCH; e-ISSN: 2196-0216 ChemElectroChem is a sister journal to Angewandte Chemie, ChemPhysChem and nine more journals of the ChemPubSoc Europe journal family. Electrochemistry in terms of basic and applied chemistry is one of the fastest- growing fi elds in chemistry today. Moreover, it has developed a strong interdisciplinary fl avour due to the emergence of bioelectrochemistry and the development of alternative energy sources. A sample of articles includes: ‘Composition-Dependent Oxygen Reduction Activity and Stability of Pt-Cu Thin Films’, ‘Promotion Effects of Sn on the Electrocatalytic Reduction of Nitrate at Rh Nanoparticles’ and ‘Topologically Sensitive Surface Segregations of Au-Pd Alloys in Electrocatalytic Hydrogen Evolution’.

Abstracts CATALYSIS – APPLIED AND PHYSICAL Ca-hydroxyapatite catalysts loaded with different ASPECTS amounts of Pt(Pt(x)/CaHAp) were synthesised and characterised by N2-adsorption, XRD, TEM, FT-IR, Mild Synthesis of Mesoporous Silica Supported UV-VIS-NIR spectroscopy and TPR. The loaded Ruthenium Nanoparticles as Heterogeneous Pt exchanged and dispersed on the apatite Catalysts in Oxidative Wittig Coupling Reactions surface, forming particles of average size 2 nm. A. L. Carrillo, L. C. Schmidt, M. L. Marín and J. C. Scaiano, The specifi c surface area of CaHAp decreased as Catal. Sci. Technol., 2014, Advance Article Pt loading increased. The catalysts were tested for A new effi cient approach for in situ synthesis of anchored dehydrogenation of butan-2-ol into MEK. The important ruthenium nanoparticles (RuNPs) in three different kinds activity at low temperatures was attributed to Pt and Pt2+ of mesoporous silica materials (MCM-41, SBA-15 and species associated with the basic Ca2+-O2– groups of the HMS) has been developed. The solids were synthesised apatite. Optimal performance for acetone conversion under very mild conditions from RuCL •H O salt reduced 3 2 to MIBK was achieved with sample loaded with in 1 h at room temperature in the mesoporous silicas 0.5 wt% Pt. At 150°C and stationary state a MIBK yield grafted with aminopropyltriethoxysilane (APTES). The Ru of 23% was obtained with a selectivity of 74%. All the nanoparticles were well dispersed with an average size Pt(x)/CaHAp catalysts showed acceptable stability of 3 nm. These materials have a molar ratio of Si:Ru = 40. over time on stream with no production of heavy Porous MOFs Supported Palladium Catalysts for compounds. Phenol Hydrogenation: A Comparative Study on MIL-101 and MIL-53 CATALYSIS – REACTIONS D. Zhang, Y. Guan, E. J. M. Hensen, L. Chen and Y. Wang, Catal. Commun., 2013, 41, 47–51 Poly (Styrene-co-Divinylbenzene) Amine Two metal organic frameworks, chromium Functionalized Polymer Supported Ruthenium Nanoparticles Catalyst Active in benzenedicarboxylates MIL-101 and MIL-53 were Hydrogenation of Xylose synthesised and used as supports for Pd catalysts. D. K. Mishra, A. A. Dabbawala and J. Hwang, Catal. MIL-101 is highly hydrophilic and benefi cial as Commun., 2013, 41, 52–55 support for fi ne Pd nanoparticles, of average size The title catalyst has been evaluated for the fi rst 2.3 nm. Microporous MIL-53 is relatively hydrophobic time in hydrogenation of xylose to xylitol. The and larger Pd particles of 4.3 nm formed on the Ru/PSN catalyst was characterised by XRD, TEM external surface. The phenol adsorption behaviours and CO chemisorption. Experiments were carried on the MILs were studied with different initial phenol out using the catalyst with different Ru loading of concentrations (0.05 M, 0.1 M, 0.15 M, 0.2 M and 1.0–3.0%, at different temperatures of 100–400°C 0.25 M) at 20°C to compare surface hydrophobicity. under different H pressures of 30–55 bar and with Pd/MIL-101 showed better phenol selective hydrogenation 2 varying stirring speeds from 400–1200 rpm. The activity to cyclohexanone (>98%) under mild reaction catalyst could be reused up to four times. conditions. The results show that MIL-101 is superior to the MIL-53 as a support when aqueous PdCl2 is used as An Effective Strategy for Immobilizing a a precursor. Homogeneous Palladium Complex onto Silica: Efﬁ cient and Reusable Catalyst for Suzuki- CATALYSIS – INDUSTRIAL PROCESS Miyaura Reactions C. Sarmah, D. Sahu and P. Das, Catal. Commun., 2013, 41, Characterization and Performance of the 75–78 Bifunctional Platinum-Loaded Calcium- Hydroxyapatite in the One-Step Synthesis of Methyl A strategy to immobilise a homogeneous Pd complex Isobutyl Ketone onto silica gel by introducing 4-pyridinecarbaldehyde N. Takarroumt, M. Kacimi, F. Bozon-Verduraz, L. F. Liotta and into the coordination sphere of Pd has been M. Ziyad, J. Mol. Catal. A: Chem., 2013, 377, 42–50 investigated. The material was characterised by FTIR,

BET measurements, XRD, SEM-EDX and ICP-AES. oxidative conditions. The Rh particles supported on The supported material is an efficient catalyst for Zr-La-O maintained their low oxidation state during the Suzuki-Miyaura reactions of aryl halides with the reaction. low Pd loading, 0.04 mol%, in an environmentally friendly reaction. The reaction proceeded smoothly FUEL CELLS and 96% 4-methoxybiphenyl was isolated after 6 h reaction time. The Electrooxidation Mechanism of Formic Acid on Platinum and on Lead ad-Atoms Ruthenium-Catalyzed ortho-C-H Modified Platinum Studied with the Kinetic Halogenations of Benzamides Isotope Effect L. Wang and L. Ackermann, Chem. Commun., 2014, 50, M. Bełtowska-Brzezinska, T. Łuczak, J. Stelmach and R. (9), 1083–1085 Holze, J. Power Sources, 2014, 251, 30–37 The first Ru-catalysed ortho-selective C–H Poisoning of the electrode surface by CO-like species halogenations on arenes through C–H activation was prevented by suppression of dissociative are reported. A catalytic system of Ru3(CO)12 and chemisorption of FA due to a fast competitive AgO2C(1-Ad) allowed site-selective brominations underpotential deposition of lead ad-atoms on and iodinations on amides with ample scope and the Pt surface from an acidic solution containing excellent functional group tolerance. Preliminary Pb2+ cations. HCOOH was oxidised 8.5 times faster mechanistic studies provided evidence for a on a Pt/Pb electrode than DCOOD. C–H and O–H reversible C–H metallation event. bonds were shown to be simultaneously cleaved in the rate determining step. C–H bond cleavage was EMISSIONS CONTROL found to be accomplished by C–OH and not O–H bond split during FA decomposition. Self-Regeneration of Three-Way Catalyst

Rhodium Supported on La-Containing ZrO2 in an Oxidative Atmosphere PHOTOCONVERSION H. Kawabata, Y. Koda, H. Sumida, M. Shigetsu, A. Takami A Simple Synthetic Route to Obtain Pure and K. Inumaru, Catal. Sci. Technol., 2013, Accepted Manuscript Trans-Ruthenium(II) Complexes for Dye- Sensitized Solar Cell Applications Rh supported on lanthanoid (La, Ce, Pr or Nd)- C. Barolo, J. H. Yum, E. Artuso, N. Barbero, D. Di Censo, containing ZrO2 was investigated as a TWC, following M. G. Lobello, S. Fantacci, F. De Angelis, M. Grätzel, M. an ageing treatment by oxidation at 1273 K to K. Nazeeruddin and G. Viscardi, ChemSusChem., 2013, 6, simulate 80,000 km in real vehicles. The properties (11), 2170–2180 of Rh were assessed by TEM, CO chemisorption and A synthetic route to obtain a functionalised TPR using CO. The aged catalyst exhibited superior quaterpyridine ligand and its trans-dithiocyanato Ru activity for the steam reforming reaction. The complex based on a microwave-assisted procedure hydrogen produced reduced the previously oxidised is presented. This Ru and quaterpyridine ligand Rh in Rh/Zr-La-O, regenerating the catalyst. The complex is used as a sensitiser in dye-sensitised solar results highlight the potential of the present strategy cells yielding a short circuit photocurrent density of for developing active TWC with high tolerance to >19 mA cm–2 with broad incident photon to current

C. Sarmah, D. Sahu and P. Das, Catal. Commun., 2013, 41, 75–78 O OH EtO O O Si N=CH N P Toluene [Pd] O OH + EtO Si O Si NH2 Pd (CIO4)2 NH2 Reﬂ ux, Ethanol, O OH EtO N2 O Reﬂ ux O Si N=CH N N O

SiO2 APTES SiO2 @APTES SiO2 @APTES-Pd

conversion effi ciency spectra ranging from 400–900 of deposition was dependent on precursor and nm, exceeding 80% at 700 nm. aqueous solution ageing. Cyclic voltammetry showed hydrogen de/adsorption peaks with CHEMISTRY magnitude proportional to the amount of Ir deposited. Tafel plots showed slope decrease from Growth of Concave Polyhedral Pd 120 mV, typical of bare Ni, down to 40 mV typical of Nanocrystals with 32 Facets through in situ pure Ir. Facet-Selective Etching Z-c. Zhang, F. Nosheen, J-c. Zhang, Y. Yang, P-p. Wang, J. Zhuang and X. Wang, ChemSusChem, 2013, 6, (10), MEDICAL 1893–1897 Cyclic RGD-Linked Polymeric Micelles for Concave Pd polyhedra have been successfully Targeted Delivery of Platinum Anticancer Drugs prepared by selectively etching the {100} facets to Glioblastoma through the Blood-Brain Tumor – in situ by I ions. Due to the presence of a high density Barrier of atomic steps and surface relaxation, the concave Y. Miura, T. Takenaka, K. Toh, S. Wu, H. Nishihara, M. R. Kano, Pd polyhedra exhibit an enhanced electrocatalytic Y. Ino, T. Nomoto, Y. Matsumoto, H. Koyama, H. Cabral, N. activity towards ethanol oxidation. Nishiyama and K. Kataoka, ACS Nano, 2013, 7, (10), 8583– 8592 A highly effi cient drug delivery to intractable human ELECTRONICS glioblastoma (U87MG) tumours has been achieved by Efﬁ cient Electronic Communication of Two using a Pt anticancer drug incorporating polymeric Ruthenium Centers through a Rigid Ditopic micelle with cyclic Arg-Gly-Asp (cRGD) ligand N-Heterocyclic Carbene Linker molecules. A rapid accumulation and high permeability M. Nussbaum, O. Schuster and M. Albrecht, Chem. Eur. J., from vessels into the tumour parenchyma was revealed. 2013, 19, (51), 17517–17527 The selective and accelerated accumulation of cRGD/m A ditopic benzobis(carbene) ligand precursor into tumours occurred via an active internalisation containing a chelating pyridyl moiety was prepared pathway (possibly transcytosis), thereby producing and used to obtain bimetallic Ru complexes by signifi cant antitumour effects in an orthotopic mouse transmetalation. The two metal centres were found model of U87MG human glioblastoma. to be electronically decoupled when the Ru is in a pseudotetrahedral geometry imparted by a cymene NANOTECHNOLOGY spectator ligand. Ligand exchange of the Cl−/cymene ligands for two bipyridine or four MeCN ligands induced Pure Platinum Nanostructures Grown by a change of the coordination geometry to octahedral. Electron Beam Induced Deposition As a consequence, the Ru centres, separated through C. Elbadawi, M. Toth and C. J. Lobo, ACS Appl. Mater. space by more than 10 Å, became electronically Interfaces., 2013, 5, (19), 9372–9376 coupled, evidenced by two different metal-centred A method for localised, mask free deposition of high- oxidation processes. These results demonstrate the purity Pt employs room-temperature, direct-write EBID effi ciency of carbenes and, in particular, of the bbi using the precursor Pt(PF3)4, and a low temperature ligand scaffold for mediating electron transfer and for (400°C) postgrowth annealing in H2O. This annealing the fabrication of molecular redox switches. removes phosphorus contaminants. The resulting Pt is indistinguishable from pure Pt fi lms by WDS. ELECTROCHEMISTRY PHYSICAL METHODS Activation of Nickel for Hydrogen Evolution by Spontaneous Deposition of Iridium Osmium Isotope Evidence for a Large Late M. Duca, E. Guerrini, A. Colombo and S. Trasatti, Triassic Impact Event Electrocatalysis, 2013, 4, (4), 338–345 H. Sato, T. Onoue, T. Nozaki and K. Suzuki, Nature Commun., Activation of Ni electrodes was performed by 2013, 4, 2455 deposition of Ir from HCI solutions of IrCl2. Effi ciency A report on the Os isotope fi ngerprint of an

extraterrestrial impact from Upper Triassic chert successions in Japan is presented. Os isotope data exhibit a marked negative excursion from an initial Os 187 188 isotope ratio ( Os: Osi) of ~0.477 to unradiogenic values of ~0.126 in a PGE-enriched claystone layer. The timing of the Os isotope excursion coincides with both elevated Os concentrations and low Re:Os ratios. The magnitude of this negative Os isotope excursion is comparable to those found at Cretaceous- Paleogene boundary sites. The geochemical lines of evidence demonstrate that a large impactor of 3.3–7.8 km in diameter, produced a global decrease in seawater 187Os:188Os ratios in the late Triassic.

Patents CATALYSIS – APPLIED AND PHYSICAL under the infl uence of a Pt catalyst. The ASPECTS silicone rubber contains 40--70 wt% of a cyano- organophosphorus compound and/or 10--150 wt% Producing a Ruthenium Catalyst of a modifi ed aluminium hydroxide with Kyoto University, Japanese Appl. 2013-115,378 respect to the amount of polyorganosiloxane. A method for producing a Ru catalyst is claimed. Ru supported by a metal oxide is pretreated with CATALYSIS – REACTIONS an aldehyde compound, a phosphorus compound and a lower alcohol compound. This Ru catalyst Producing Ethanol Using Rhodium Catalysts can be used for producing an alkyl group- or Celanese International Corporation, US Appl. 2013/8,536,383 alkenyl group-substituted compound. Treating this A process for producing ethanol involves hydrogenating tris(acetylacetonato) Ru catalyst supported on acetic acid in the presence of a hydrogenation catalyst cerium oxide with formaldehyde, triphenylphosphine containing Rh and Sn. The molar ratio of Rh to Sn is and methoxyethanol gave a catalyst useful for adding from 20:80 to 80:20. The Rh and Sn are present in styrene on -tetralone. 0.1 wt% to 25 wt% based on total weight of the catalyst; the metal loading of rhodium is from 0.5 wt% to Manufacture of Supported Ruthenium Oxide 2 wt%. The catalyst may further contain an active metal Sumitomo Chemical Co, Ltd, Japanese Appl. 2013-169,517 selected from Co, Zn, Cr, Cu, Pt, Pd, Ni, Fe, W, Mo, V and A supported Ru oxide is manufactured by contact combinations thereof. The hydrogenation is performed treatment of a support with a solution containing a in the vapour phase at a temperature from 250--375ºC; Ru compound, drying in a gas stream while stirring, with a pressure of 10 kPa to 3000 kPa, and a hydrogen and fi ring in an oxidising gas atmosphere. Preferably, to acetic acid mole ratio greater than 4:1. The support the support contains TiO2, A l 2O3 and/or SiO2. The is selected from silica, silica/alumina, pyrogenic silica, supported Ru oxide is used in preparation of Cl2 by high purity silica, carbon, alumina, and mixtures oxidation of HCl. thereof. This support is present in 25 wt% to 99 wt%, Magnetic Nanoparticle Supported Osmium based on total weight of the catalyst. The acetic acid Oxide Catalyst conversion is greater than 30%. National Institute of Advanced Industrial Science & Technology, Japanese Appl. 2013-181,025 EMISSIONS CONTROL Magnetic nanoparticle (Fe O ) supported Os oxide 3 4 Palladium and Gold Catalysts catalysts for dihydroxylation of an olefi n are prepared. WGCH Technology Ltd, US Appl. 2013/0,217,566 During dihydroxylation the title catalysts exhibit little leaching of Os. As an example, a Fe3O4 nanoparticle An emission control catalyst for treating an engine supported compound was synthesised by reaction exhaust includes an oxide carrier, and Pd particles of Fe3O4, K 2OsO4 and a precursor. The compound and Au particles supported on the oxide carrier. The is used as a catalyst for dihydroxylation of trans-- catalyst has a Pd to Au weight ratio in a range of about methylstyrene. 0.5:1 to about 1:0.5. The emission control catalyst further comprises a substrate having a honeycomb CATALYSIS – INDUSTRIAL PROCESS structure with gas fl ow channels, wherein the oxide carrier and the Pd and Au particles are coated on the Electrically Insulating Material using Platinum walls of the gas fl ow channels. A second oxide carrier Catalyst may have Pt and Pd particles. An example is given OAO KZSK, Russian Patent, 2,490,739; 2013 of a supported catalyst containing 1% Pd and 2% Au Insulating material is claimed based on addition prepared by adding 1% Pd, 2% Au colloid solution to curing a silicone rubber containing both vinyl and a fl ask while stirring; adding MI-386 alumina powder hydride-containing silicones and fi llers, crosslinked to the fl ask, and then stirring the mixture for 18 h. The

mixture is then fi ltered and dried at 130ºC for 3 h, and metals, then dissolving the rinsed Ru hydroxide in then ground to a fi ne powder. The powder is calcined nitric acid. in air at 500ºC for 2 h using a heating ramp rate of --1 8ºC min . ELECTRICAL AND ELECTRONICS Structure Comprising Ruthenium Metal FUEL CELLS Micron Technologies Inc, US Appl. 2013/0,221,420 Gas Diffusion Electrode Applying Platinum A semiconductor device includes a smooth Ru metal Nanowires layer which may form a capacitor bottom plate or a The University of Birmingham, World Appl. 2013/128,163 transistor gate such as a control gate. The smooth Ru A gas diffusion electrode comprising a gas diffusion may be on an oxide such as a gate oxide. The thickness layer with a surface to which Pt nanowires have of the Ru layer may be 150--800 Å and there may been applied and the surface is at least partially optionally be a capping material of thickness 100--500 Å. weakly hydrophobic or hydrophilic is claimed. The Ruthenium Seed Layer in a Magnetic Recording Pt nanowires are applied substantially or on regions Medium of the surface. The surface area may be 50--100% Hitachi Global Storage Technologies, US Appl. weakly hydrophobic or hydrophilic. The gas diffusion 2013/0,235,490 layer has a water contact angle less than 130º. The Pt An apparatus is claimed with a perpendicular magnetic nanowires cover 75--99% of the total surface. These are recording medium including a substrate, a soft uniformly distributed. The Pt nanowires are of length underlayer above the substrate, a seed layer structure 50--500 nm, with a diameter 1--10 nm. The nanowires which contains Ru and a magnetic recording layer form a catalyst layer of thickness 50 nm--1 μm. The gas above the Ru seed layer. The seed layer structure is 10 diffusion layer is selected from carbon cloth or carbon nm or less in thickness. This structure has composition paper. of NiW (2--10 at%) Ru (3--9 at%). The concentration of Polymer Electrolyte Fuel Cells Ru is 3--9 at%. Toshiba Corp, Japanese Appl. 2013-178,963 The title fuel cells have a MEA with a Ru-containing ELECTROCHEMISTRY anode catalyst layer and a Pt-containing cathode Mesostructured Thin-Films as Electrocatalysts catalyst layer. Either (i) a means for application of V. Stamenkovic and N. Markovic, US Appl. 2013/0,209,898 voltage above its open circuit voltage is provided or (ii) the anode catalyst layer, the electrolyte layer or The manufacturing of thin fi lm catalysts comprises of their interface contains a catalyst to oxidise Ru(III) (i) providing a substrate; (ii) providing a source of Pt to Ru(IV) or Ru(III) adsorbent. The PEFC is operated group metal and alloying metal; (iii) using physical with application of voltage higher than its open circuit vapour deposition to deposit both metals; and (iv) voltage under open circuit conditions and the output annealing the thin fi lm at a temperature of 300--400ºC, can be recovered by reactivating the cathode catalyst. forming a morphology of (111) hexagonal faceted surface grain structure in the thin fi lm having a

catalytic activity approaching Pt3Ni(111). The Pt group CHEMISTRY metal is selected from Pt, Pd and Rh. The transition Manufacture of Aqueous Ruthenium Nitrate metal is selected from Fe, Co, Ni, V and Ti. The thin fi lm Solutions electrocatalyst thickness is about 5--20 nm. Tanaka Noble Metal Industrial Co Ltd, Japanese Appl. 2013- 180,936 MEDICAL Aqueous Ru nitrate solution of <1000 ppm Cl is prepared by neutralisation of a starting aqueous Ru Platinum Based Antitumour Agent nitrate solution with alkali hydroxide (e.g. KOH, to pH 8--13), Yamaguchi University, Japanese Appl. 2013-155,159 rinsing the formed Ru hydroxide with dilute nitric A polymeric antitumour agent characterised acid ≥1 time(s) to remove the hydroxide-derived alkali by containing an ionic complex of a Pt-based

antitumour agent and a styrene-maleic acid based copolymer is disclosed. The agent containing 1 (R )a A the ionic complex is accumulated in a tumour site due to enhanced permeability and retention C1 2 effect. In an example, cisplatin and styrene-maeic C lr L3-n acid copolymer were reacted, and the obtained C3 ionic complex was freeze-dried to give stable N1 nanoparticles, which inhibited proliferation of HeLa 2 B cells with an IC50 value of 104.1 μm. (R )b n 1

NANOTECHNOLOGY World Appl. 2013/105,615 Imaging Mass Analysis Using Platinum alkyl, alkenyl, aryl, aralkyl, alkoxyl, arylalkoxyl; R1--R8 = H, Nanoparticles halo, (cyclo)alkyl, alkenyl, aryl, aralkyl, alkoxyl, aryloxyl, Nissan Chemical Industries Ltd, World Appl. 2013/122,225 dialkylamino, alkylsily; L1, L 2 = electronically neutral A method for imaging mass analysis is characterised monodentate phosphine ligand; L1L2 may form a bidentate by preparing a sample by physical vapour deposition phosphine ligand. The title complexes can be used in of Pt nanoparticles. This provides an improved method electroluminescent devices that emit light from blue to green. for imaging mass analysis using a matrix to assist in ionising a sample with high ionisation effi ciency, reduction in visible information and migration, REFINING & RECOVERY absence of interference peaks originating from the Separating Platinum Sulﬁ des matrix and high spatial resolution. OAO Krastsvetmet, Russian Patent, 2,490,349; 2013 The invention involves pulping a concentrate of Pt PHOTOCONVERSION and Re sulfi des in an aqueous ammonia solution. The pulp is treated with hydrogen peroxide solution Iridium Complexes Contained in Luminescent Materials at a temperature of 25--45ºC. This reaction mixture is acidifi ed with sulfuric acid until a pH 0.2--2.0 is Mitsubishi Chemical Corp, World Appl. 2013/105,615 achieved. This is heated and aged. The precipitate of Pt The title complexes show good organic solvent solubility, compounds is separated from the solution by fi ltering. and can be stored without precipitation. The title organic The effect is to enable separation of Pt at the step for electroluminescent devices, preferably having emitter layers extracting Re from a sulfi de concentrate. containing charge-transporting N-containing aromatic heterocyclic compounds as hosts and the complexes as dopants, have a low operating voltage and long service life. The SURFACE COATINGS title complexes are represented by 1 (A = 5- or 6-membered Films with Absorbent Palladium Coating aromatic hydrocarbon ring or aromatic heterocycle including Morgan Adhesives Company, European Appl. 2,626,379; 1 2 carbon atoms C and C ; B = 5- or 6-membered aromatic 2013 heterocycle including carbon atom C3 and nitrogen atom A multilayer fi lm has a polymeric fi lm layer and N1; L = organic ligand; p, q= 1--4; n = 1--3; R1, R 2 = substituent; an absorbent layer containing a Pd complex. The >1 of R1 and R2 = (Ar1Z) X ; X = C (hetero)arylene; m m1 6--20 absorbent layer also contains at least one of a Ar1 = C (hetero)aryl; Z = [C(R) ; R = H, F, Cl, Br, 3--20 2 cyclodextrin, a hydrophobin protein, or a derivative C alkyl, etc.; m = 1--3; m1 = 0--3; m2 = 1--20). 1--20 thereof and is effective to absorb an odour, a volatile organic compound or both. The absorbent layer Platinum Phosphine Diphenyl Ether Derivative comprises between 0.1--0.75 wt% Pd complex, 2--7 wt% of Complexes cyclodextrin and 0.1--0.5 wt% of hydrophobin protein. Ube Industries, Ltd, Japanese Appl. 2013-155,131 The polymeric fi lm layer comprises at least one of 1 2 1–4 The title complexes are represented by [L L Pt(o-C6(R )4-X- polyethylene, polypropylene, polyvinyl chloride and 5–8 9 9 o-C6(R )4]where X = O, S, NR , silylene; R = H, halo, (cyclo) polyethylene terephthalate. The absorbent layer has a

surface area between 280--320 cm2 and when placed in a chamber having a volume of 400 cm3 with 2 ml of an n-butanol saturated atmosphere injected into the chamber it absorbs greater than 80% of the n-butanol in 1 h.

Sulfonation of Plastic and Composite Materials M. Wotjtaszek et al., US Appl. 2013/0,209,689 A method of preparing a plastic article to accept plating is claimed. A portion of the plastic article is rendered plateable by sulfonation by: (i) exposing the plastic article to an atmosphere containing a sulfonating agent to sulfonate at least a portion of the plastic article; (ii) contacting the sulfonated plastic article with a conditioner; (iii) contacting the plastic article with a Pd metal activator so that the noble metal is adsorbed on at least a portion of the surface of the plastic article; and (iv) contacting the plastic article with an accelerator to react with the adsorbed Pd to increase the catalytic activity of the adsorbed noble metal towards plating. The plastic may be selected from poly(ether-ether-ketone) resins, polyamide, polyethylene, polypropylene, etc., or a combination. The sulfonating agent comprises fuming sulfuric acid or vapour phase sulfur trioxide. Timing of contact between the sulfonating agent and the plastic article is between 1 sec and 60 min.

Obtaining Platinum Group Metal Coatings FGUP Radievyl Institut im. V. G. Khlopina, Russian Appl. 2,489,516; 2013 An invention to help obtain pore-free microcrystalline coatings with high adhesion to substrate materials is claimed. Coatings are obtained from Ir or Rh by a thermal decomposition process at a temperature between 250--450ºC and pressure 0.01--0.05 mm Hg. The precursors are Ir tetratrifl uorophosphine hydride of formula Hlr(PF3)4 or Rh tetratrifl uorophosphine hydride of formula HRh(PF3)4.

FINAL ANALYSIS

Effects of Platinum Group Metals Doping on Stainless Steels

The positive effects of palladium and ruthenium on within the microstructure, which has a controlling the corrosion properties of titanium alloys are well effect on the benefi ts gained, is much harder to predict known and led to the development of new grades in stainless steels. Further, the OCP of a stainless steel to extend the operating window for titanium alloys in an oxidising solution is close to the transpassive (1). The same mechanism, cathodic modifi cation, region. Adding pgms will increase the OCP further, should also function in any alloy that is protected by potentially out of the passive region and into the a corrosion resistant oxide fi lm. This is the case for transpassive region, which allows attack to occur. stainless steels, which typically rely on a chromium oxide fi lm to protect the alloy. Corrosion in Doped Steels Corrosion in pgm doped stainless steels is therefore Passivation Behaviour dependent on the alloy composition and the Cathodic modifi cation refers to the increase in environment that the steel is exposed to. Corrosion in cathodic activity caused by the presence of platinum stainless steels occurs at breaches in the oxide fi lm. group metal (pgm) at the surface of the metal. This These are discrete and the initial breaches cause causes an increase in the cathodic current at any metastable pits to form, which will only stabilise if the given potential, which will increase the open circuit diffusion distance out of the pit is suffi ciently long to potential (OCP) to higher voltages. Classical Tafel present a barrier to loss of the solution within the pit. behaviour would show that the increased OCP would Pitting is a therefore a localised phenomenon and also lead to a higher anodic current (increasing as such the location of the pgm relative to the pit is corrosion) (2, 3). However, passivating alloys do not important to the corrosion resistance. One technique follow Tafel behaviour at all potentials, due to the for investigating this is electron probe micro analysis formation of a passive region (where the passive fi lm (EPMA), which produces high resolution elemental dominates the behaviour). The increase in cathodic maps of the surface. EPMA on polished sections potential can push the OCP into this passive region, through pits in ruthenium-doped 304 stainless steel preventing corrosion. If the increase in OCP is not high showed that the ruthenium was enriched by the pit enough to reach the passive region, some dissolution edge compared to the bulk (Figures 1(a) and 1(b)), will occur. However, during this dissolution the pgm as predicted by the theory outlined above. This implies will not dissolve into solution and more pgm will be that some regions within the pit will become cathodic revealed as the other metals do dissolve. This leads with respect to the bulk, potentially allowing cathodic to an enrichment of the surface in pgm, which will processes to operate within the pit. The results of increase the cathodic modifi cation, pushing the this are likely to be system specifi c and could be OCP further towards the passive region and often investigated by artifi cial pit studies. passivating the alloy (4). Stainless steels are more complicated than titanium Platinum Group Metal Doping and Chloride Ions alloys, due to both design (more elements are added Pits are more common in chloride containing to provide specifi c functions) and the use of recycled solutions, though the exact mechanism by which scrap steel in their production. The location of the pgm chloride causes fi lm breakdown is not agreed

Level Ru Level 1592 508 1393 444 1194 381 995 317 796 254 597 190 398 127 199 63 0 0 Average 326 Average 108

200 μm 200 μm Ru Fig. 1. (a) Secondary electron image of a section through a pit in ruthenium-doped 304 stainless steel showing the topography of the surface; (b) ruthenium concentration map of the section through the pit showing the increased level of ruthenium at the pit edge

(5–7). Chloride containing environments have also Palladium doped 304 showed a much lower current presented a situation where the choice of doping than the undoped steel during potentiodynamic pgm is important. Electrochemical studies coupled testing (Figure 2(b)). However, after the experiment with examination of the surfaces following the was completed, it was discovered that the surface of electrochemical testing on samples of 304 doped with the alloy had disintegrated into powder. It is believed either palladium, ruthenium or undoped, in solutions that this powder had acted as an insulating layer on containing 0.05 M sulfuric acid and 0.1 M sodium the surface, reducing the current passed. Analysis of chloride clearly showed the possible outcomes the powder showed a much higher palladium content (Figures 2(a)–(c)). than the doping level, which can be explained by Undoped 304 rapidly initiated pits at the exposed remembering that the other elements are dissolving surface (Figure 2(a)). As expected these pits initiated into the solution. under lacy covers of oxide fi lm which provide the Ruthenium doped 304 showed virtually no sign increased diffusion distance required to maintain the of attack (Figure 2(c)) and the measured current aggressive solution within the pit. density was orders of magnitude lower than had

(a) (b) (c)

100 μm 100 μm 100 μm

Fig. 2. Corrosion damage on: (a) undoped 304 stainless steel; (b) palladium doped 304; and (c) ruthenium doped 304 following electrochemical testing

been measured on the undoped steel. This shows content at the grain boundary prevents the formation that the steel was well protected by the addition of of the protective oxide fi lm and the boundary will be ruthenium. anodic with respect to the rest of the steel, which For a further practical example of how pgm will galvanically drive the corrosion of the grain doping can protect a steel, the effect of ruthenium on boundary. However, during corrosion, ruthenium will sensitisation in 304 stainless steel can be considered. become enriched at the grain boundary, increasing Sensitisation is a degradation mechanism operating the OCP. As corrosion continues, the enrichment in stainless steels that are heated to between continues, further increasing the OCP of the grain 500ºC and 800ºC. At these temperatures, chromium boundary. Once this OCP rises suffi ciently for the diffuses to the grain boundaries to form chromium grain boundary to be cathodic with respect to the rest carbides, resulting in the formation of chromium of the steel, the corrosion at the grain boundary will depleted regions by the grain boundary. These cease. EPMA mapping of a corroded grain boundary allow intergranular attack to develop in corrosive in such a steel clearly showed both the formation media. In ruthenium doped steels, the formation of of chromium carbides at the grain boundary and carbides was observed, however the alloy resisted increased ruthenium content along that same grain corrosive attack beyond a slight etching of the grain boundary (Figures 3 and 4). boundaries. This observation can be explained by considering Conclusions the local electrochemical potentials and the effect of While not as consistently benefi cial as additions of ruthenium on these. Initially, the reduced chromium palladium have been seen to be in titanium grade 7,

Fig. 3. Carbon C Elemental Percents EPMA map showing concentration increases at a 140 3 grain boundary in a sensitised 2.8 304 doped steel 2.6 sample 135 2.4 2.2 130 2.0 1.8 1.6 125 1.4 Y, mm Y, 1.2 120 1.0 0.8 115 0.6 0.4 0.2 110 90 95 100 105 110 115 X, mm

Fig. 4. Ruthenium Ru Elemental Percents EPMA map showing concentration increases at a grain boundary in 140 1.45 a sensitised 304 doped 1.4 steel sample 1.35 135 1.3 1.25 1.2 130 1.15 1.1 1.05 125 Y, mm Y, 1 0.95 120 0.9 0.85 0.8 115 0.75 0.7 0.65 110 0.6 90 95 100 105 110 115 X, mm

additions of the correct pgm to stainless steels can 6 V. S. Agarwala and G. J. Biefer, Corrosion, 1972, 28, increase the corrosion resistance of the steel. To (2), 64 successfully protect steels in this manner, the corrosive 7 T. Itagaki, H. Kutsumi, H. Haruyama, M. Igarashi and environment and the pgm additions must be carefully F. Abe, Corrosion, 2005, 61, (4), 307 considered. The location of the pgm within the steel The Authors can greatly affect its local protectivity. Andrew Fones is a Research Scientist at ANDREW FONES* and GARETH D. HATTON the Johnson Matthey Technology Centre, Johnson Matthey Technology Centre, Blounts Court, Sonning Common, UK, working in the Sonning Common, Reading RG4 9NH, UK Platinum Group Metals Applications group. He is a corrosion scientist with a *Email: [email protected] materials background, interested in the effects of platinum group metals doping on alloys. References 1 R. W. Schutz, Corrosion, 2003, 59, (12), 1043 2 Platinum Metals Rev., 1958, 2, (4), 117 Gareth Hatton received his BSc in Archaeological Sciences at the University 3 J. H. Potgieter and H. C. Brookes, Corrosion, 1995, 51, of Bradford in 2000. Subsequently he (4), 312 undertook a DPhil at the University of Oxford working on the analysis and 4 M. A. Streicher, Platinum Metals Rev., 1977, 21, (2), 51 replication of ancient vitreous materials. 5 E.-S. M. Sherif, J. H. Potgieter, J. D. Comins, L. Cornish, P. He joined the electron microscopy group at Johnson Matthey in 2005 where he A. Olubambi and C. N. Machio, Corros. Sci., 2009, 51, specialises in the application of EPMA. (6), 1364

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