The Taylor Conference 2009 CONVERGENCE BETWEEN RESEARCH and INNOVATION in CATALYSIS

DOI: 10.1595/147106709X474307 The Taylor Conference 2009 CONVERGENCE BETWEEN RESEARCH AND INNOVATION IN CATALYSIS Reviewed by S. E. Golunski§ and A. P. E. York*‡ Johnson Matthey Technology Centre, Blounts Court, Sonning Common, Reading RG4 9NH, U.K.; and ‡Department of Chemical Engineering and Biotechnology, University of Cambridge, New Museums Site, Pembroke Street, Cambridge CB2 3RA, U.K.; *E-mail: [email protected] The Taylor Conferences are organised by the Professor Gabor Somorjai (University of Surface Reactivity and Catalysis (SURCAT) Group California, Berkeley, U.S.A.) developed the theme of the Royal Society of Chemistry in the U.K. (1). that progress in catalysis is stimulated by revolu- The series began in 1996, to provide a forum for tionary changes in thinking. He predicted that, discussion of the current issues in heterogeneous whereas in previous eras new catalysts were identi- catalysis and, equally importantly, to promote fied through an Edisonian approach (based on trial interest in this field among recent graduates. The and error) or discovered on the basis of empirical fourth in the series was held at Cardiff University understanding, future catalyst design will be based in the U.K. from 22nd to 25th June 2009, attract- on the principles of nanoscience. He highlighted his ing 120 delegates, mainly from U.K. academic idea of ‘hot electrons’ that are ejected from a metal centres specialising in catalysis. Abstracts of all lec- by the heat of reaction produced at active sites, but tures given at the conference are available on the which could become a potential energy source if conference website (2). The first half of the confer- they were generated by the absorption of light. ence consisted of presentations by established As described by Professor Richard Catlow researchers from the U.K., Japan and the U.S.A., (University College London, U.K.) and Stephen with each presentation afforded ample time for Jenkins (University of Cambridge, U.K.), quantum debate and discussion. The format of the second mechanical techniques for modelling many- half was similar, but with a key difference: the pre- electron systems lend themselves to the study of senters were some of the postgraduate students catalytic materials and catalytic reaction pathways. and postdoctoral researchers who, it is hoped, will Professor Catlow’s particular expertise lies in the become the future generation of catalysis experts. study of defective metal oxides, and the way in which they interact with metal particles. In the case Concepts, Theories and Methodology of palladium deposited on ceria, his models predict Professor Sir Hugh Taylor, after whom the an increase in the concentration of Ce3+ species Taylor conferences are named, was a pioneer in resulting from electron transfer from the metal to the study of chemisorption and catalysis on metals the metal oxide. Jenkins has been examining the and metal oxides (3). As Professor Frank Stone likelihood of specific reaction steps taking place on (Emeritus Professor of Chemistry, University of the surface of supported metal catalysts. For both Bath, U.K.) reminded us in his opening address, alkane synthesis and combustion, his calculations H. S. Taylor (as he was known in his time) was implicate a common formyl intermediate, which is responsible for introducing the concepts of acti- not readily detected by spectroscopic techniques. vated adsorption and of the active site, both of However, Professor Charles Campbell (University which were highly controversial when he first of Washington, U.S.A.) cautioned against an over- proposed them around 1930 (4), but which have reliance on surface modelling. Based on classical become fundamental to our understanding of microcalorimetric measurements, he has shown many catalytic phenomena. that density functional theory (DFT) underpredicts §Present address: Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K. Platinum Metals Rev., 2009, 53, (4), 221–225 221 the heat of adsorption for a variety of molecules Mellon University, U.S.A.) separately described (for example, carbon monoxide, cyclohexene and the complex dependence of enantioselective reac- aromatics) on a range of surfaces (such as carbon, tions on surface composition and structure. precious metals or metal oxides). As explained by Professor James Anderson (University of Aberdeen, U.K.), in the context of Taking a View alkyne hydrogenation, poor selectivity is often the Professor Lynn Gladden (University of result of heterogeneity in the exposed sites, even Cambridge) described how macroscopic and on apparently clean and compositionally homoge- microscopic events can be tracked in an optically neous surfaces. Through targeted use of additives, opaque system, such as a catalytic reactor. Using such as bismuth in the case of palladium-based magnetic resonance imaging (MRI) – essentially the hydrogenation catalysts, specific non-selective same technique as used diagnostically in medicine – sites can be deliberately blocked. she has been able to observe the liquid flow fields During the direct synthesis of hydrogen perox- that develop in packed bed reactors. By combining ide from hydrogen and oxygen, the combustion of the images with measurements from temperature hydrogen and the over-hydrogenation of hydrogen sensors, detailed reaction profiles can be produced peroxide to water need to be suppressed. for steady-state and dynamic operating conditions. Professor Graham Hutchings (Cardiff University, On a different scale, Professor Chris Kiely U.K.) has shown that gold-palladium catalysts are (Lehigh University, U.S.A.) has used dark-field among the most effective, but their performance imaging techniques to detect the smallest metallic, can be sensitive to the support material used. In bimetallic and metal oxide particles (less than 1 nm collaboration with Professor Kiely, he has found in diameter) by electron microscopy. In what may that the nature of the dispersed gold-palladium can become a seminal study, he has correlated the high vary, with core-shell particles (on titania and CO-oxidation activity of a specific gold/iron oxide alumina) producing lower yields of H2O2 than (Au/Fe2O3) catalyst with the presence of two- palladium-rich alloy particles (on carbon). Both layer, 0.5 nm-diameter gold clusters. types of core-shell particle, those with a gold core The importance of studying catalysis over a and palladium shell and those with a palladium core range of scales was emphasised by Professor and gold shell, were less active than the palladium- Trevor Rayment (Diamond Light Source Ltd, gold alloy. U.K.). The new U.K. synchrotron light source is Professor Masatake Haruta (Tokyo Metropoli- intended to provide understanding of ‘real tan University, Japan) has found that small gold catalysts, under real conditions, in real time’ (5). clusters can selectively catalyse some particularly One of the ambitions is to increase the through- challenging reactions. The outstanding example is put for techniques such as X-ray absorption the selective insertion of oxygen into propylene to spectroscopy, by reducing the amount of non- form propylene oxide, which is currently produced productive beam time. Although the Diamond by indirect processes that produce large quantities facilities are not expected to provide the tools for of waste byproducts. By reactively grinding a non- catalyst discovery, it is hoped that they can accel- chloride Au(III) precursor with titanium silicalite erate the development process by identifying the (TS-1), Professor Haruta has dispersed the gold as critical relationships between catalyst structure 1.6 nm particles, which can activate propylene to and performance. react with O–O–H species formed from oxygen and water at the metal-support interface. Controlling Selectivity Stressing a point made by Professor Somorjai Promoting and Maintaining Activity that catalysis in the 21st century is all about selec- Vanadia supported on θ-alumina is one of the tivity, Chris Baddeley (University of St Andrews, best catalysts for butane dehydrogenation, but the U.K.) and Professor Andrew Gellman (Carnegie rate of reaction is very sensitive to the vanadia Platinum Metals Rev., 2009, 53, (4) 222 loading. Professor David Jackson (University of air quality led to the development of technology Glasgow, U.K.) reported that maximum activity for catalytic aftertreatment using pgm catalysts (7). coincides with the presence of a mainly polymeric This highly effective technology does not, howev- form of vanadate species which covers most of the er, address the global problem of greenhouse gas alumina surface. However, another key perfor- emissions, which is now the prime motivator for mance criterion is durability. During butane the introduction of fuel cells. dehydrogenation, two forms of deactivation can Appropriately, there was an environmental be discerned: a short-term but reversible effect theme running through many of the presentations caused by deposition of carbon-rich species on in this section of the conference. For example, CO the catalyst surface, and a longer-term effect asso- oxidation was covered by Sankaranarayanan ciated with an irreversible phase change in the Nagarajan (National Chemical Laboratory, Pune, alumina. India), who looked at oxygen mobility and the role In the Francois Gault Lecture, Professor of subsurface oxygen on palladium surfaces (8, 9), Robbie Burch (Queen’s University Belfast, U.K.) Figure 1. The subject

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