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3439 Nanochemistry

Introduction Andreas Borgschulte ([email protected])

CHE729.1 Mi. 10:15-12:00 Contents of this lecture  Introduction: We are assembled nano-machines!  Nanotechnology  History, Definition  Visualization of nanostructures  Size dependent properties  Preparation of nano structures  Bottom-up approach  top-down approach  theory  Some applications  colloids  Hydrogen storage  catalysis  membranes  cell biology  Nanotoxicity  What is NOT Nanochemistry?  What are the scientific questions to be addressed? Definition / History

 Nanotechnology is the manipulation of matter on an atomic and molecular scale. Generally, nanotechnology works with materials, devices, and other structures with at least one dimension sized from 1 to 100 nanometres.

 The scanning tunneling microscope, an instrument for imaging surfaces at the atomic level, was developed in 1981 by Gerd Binnig and Heinrich Rohrer at IBM Zurich Research Laboratory

 K. Eric Drexler developed and popularized the concept of nanotechnology and founded the field of molecular nanotechnology. In 1979, Drexler encountered Richard Feynman's 1959 talk There's Plenty of Room at the Bottom.

Ref. wikipedia Liquids/gases Pyrite FeS2

1023 Perovskite CaTiO3 3-mm diamond in eclogite graphene

Diamond

Graphite Fullerene Carbon nanotubes

• Allotrope of carbon • Graphite sheet rolled into a tube • 50,000x smaller than human hair • Members of fullerene family (including buckyballs)

www.ewels.info/img/science/nano.html Single-walled nanotubes

• Capped or uncapped • All covalent sp2 bonding • Metallic conductors or semiconductors • Bundles • Defects – points for reaction Multi-walled nanotubes

• 63GPa tensile strength (steel 1.2GPa) • Inner tubes slide without friction

http://www.msm.cam.ac.uk/polymer/research/nanointroCNT.html Graphene – the new Wonder material

 Strength of graphene  Graphene has a breaking strength of 42N/m, which is more than 100 times stronger than steel  Electrical conductivity of graphene  The sheet conductivity of a 2D material is given by . The mobility is theoretically limited to μ=200,000 cm2V−1s−1 by acoustic phonons at a carrier density of n=1012 cm−2. The 2D sheet resistivity, also called the resistance per square, is then 31 Ω. Our fictional hammock measuring 1m2 would thus have a resistance of 31 Ω. σ=enμ  Using the layer thickness we get a bulk conductivity of 0.96x106 Ω-1cm-1 for graphene. This is somewhat higher than the conductivity of copper which is 0.60x106 Ω-1cm-1.  Thermal conductivity  The thermal conductivity of graphene is dominated by phonons and has been measured to be approximately 5000 Wm−1K−1. Copper at room temperature has a thermal conductivity of 401 Wm−1K−1.  Background information Noble price in Physics 2010 https://www.nobelprize.org/nobel_prizes/physics/laureates/2010/advanc ed-physicsprize2010.pdf

Picture credit: Alexander Aius, Wikipedia https://www.youtube.com/watch?v=O1WpE5ntqbQ Massless Dirac quasiparticles in graphene

 The intrinsic resistivity of graphene sheets would be 10−6 Ω⋅cm. This is less than the resistivity of silver.  Electrons behave like a wave…

1 ∗ ⋯ 2

Akin Akturk and Neil Goldsman, J. Appl. Phys. 103, 053702 (2008); A. H. Castro Neto et al., Rev. Mod. Phys., Vol. 81, 109 (2009) Theory

2          M. D. Hanwell   V R  r  (r)  (r),  2m  Schrödinger equation solvable for limited number of atoms N < 103

Nanomaterials 102 … 105 atoms Band structure in crystalline solids: Bloch functions N ~ 1023 (r  R)  (r)   0 exp2i / a

k = 0 E(k) k = 0 E0 k =  /a Oleg Shpy k = 0 k =  /a Nanoribbons for graphene transistors

Baringhaus, J.; Ruan, M.; Edler, F.; Tejeda, A.; Sicot, M.; Taleb-Ibrahimi, A.; Li, A. P.; Jiang, Z.; Conrad, E. H.; Berger, C.; Tegenkamp, C.; De Heer, W. A. Nature 506, 349–354 (2014)

J. Cai, P. Ruffieux, R. Jaafar, M. Bieri, T. Braun, S. Blankenburg, M. Muoth, A.P. Seitsonen, M. Saleh, X. Feng, K. Müllen, R. Fasel, Nature, 466, 470-473 (2010) Memory Chip Catalysis of hydrogen combustion

H combustion needs 600°C without, H 2  M  2H *M 2 proceeds at RT with Pt catalyst

H + H (E = 2.4 eV)

2H 2  O2  4H *2O*  2H 2O

Surface Reaction

Pt-nano particles on a ceramics

Catalytic hydrogen burner (Empa 2009) Döbereiner Cigar lighter (1823) Hydrogen dissociation on d-metals Solid–liquid interface: Electrochemical Double layer  with ze  kBT distance  x   exp x    Debye length   potential  1 0 r kBT 0.34 D   2  nm 2N Ae I Imol/l + water

+ - The mystery of electrochemistry

+ - + 0 0 + solid - - - +

+ T. Cosgrove, Colloid Science, Principles, methods, and applications, Wiley 2010; The hydrogen electrode: Butler‐Volmer equation

H 2  EU U / kT j  k0 ' e Pt-electrode  EU / kT j  k0 1 e

U

U chemical potential H H O-H+ 2 E e- e- + H + H2O H2O-H H+ H3O+

+ H H2O-H reaction coordinate H2 H H O-H+ 2 log j  log j0  b()U Marcus‐Theory of the charge transfer

metal metal sphere GG sphere free energy free energy

reaction ecoordinate R.A. Marcus Nobel price 1992  1 1  1 1  2 G  f (e)      e    electrostatic  r R  opt  stat  contribution 

 0 2    G  + chemical G  0 Ion 4 contribution G Transition-state Theory

 0 2    G   k(T )  exp  4k T  B  Experimental confirmation of Marcus theory

G reactant / Product I/II/III Variation of G0 at constant 

0 GI  0

0 GII

0 GIII

q=e

 0 2   G  k(T )  exp  4k T  B 

R. Marcus, Angew. Chem. lnt. Ed. Engl. 1993, 32. 1111 Electron transfer between molecules ~ Electrodes

∆ ln ∝ ln ∝ ln 1E13 4∙ 100 2

1E12 ∆ ) ) ∝ 2

-1 10 inverted region 2 1E11 k (s

j (mA/cm 1 1E10

1E9 0.1 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.5 0.4 0.3 0.2 0.1 0.0 -0.1 G (eV) U = G (eV)

B - + +

S. Murphy, et al., J. Org. Chem., 60, 2411, 1995; M. H. Miles, et al. J. Electrochem. Soc., Bd. 123, p. 332, 1976. Reorganization energy 

The inner part corresponds to the energy   v  s cost due to geometry modifications to go from a neutral to a charged geometry and vice versa.  0 2   G  k(T )  exp  The outer part corresponds to the energy 4k T  B  cost from the solvent response.

2.2

2.0

1.8

1.6 voltage (V) 1.4 0 50 100 150 200 -2  of the first electron transfer only ~0.25 eV current density (mA cm ) out of an overall excitation energy of 1.38 eV

R. Marcus, Angew. Chem. lnt. Ed. Engl. 1993, 32. 1111 Mitochondria_360p Kopie.mov Biology takes place in nano-structures

membrane thickness ~10 nm

mitochondrium Simplified spatial scheme of photosynthesis

stroma NADPH ADP + NADP +P H + H+ ATP HEC P680/ PQ cytochrome P700 Q /Q OEC PC ATP synthase 3H+ 2 H2 O + lumen 4H + O2 Alkaline water electrolyzers: electrolyte/membrane

+ O2 H2 -

gas separation by membranes l = 1mm

Lurgi, Zdansky-Lonza pressure electrolysis: (a) Bipolar electrodes, dimple plate cell partition; (b) Pre-electrodes in the form of nets on both sides of asbestos diaphragms ; (c) Asbestos diaphragms; (d) Cell frame;

(Häussinger P., et al., 2006) Silicates: crystal structure O Main unit for all silicates : Si

Quartz SiO2

SiO4 SiO4

BO SiO4 SiO4

SiO4 SiO4

SiO4 SiO4

Olivine, (Mg,Fe) SiO ) Mg1 Mg1 2 4 Mg1 Mg1 Mg1 Mg1 Mg1 Mg1 Mg1 Mg1 SiO4 SiO4

SiO4 SiO4

Mg2 Mg2 Mg2

Mg2 Mg2 Mg2 NBO Mg2 Mg2 Mg2 Mg2 Top: SEM image

SiO4 SiO4 SiO4 SiO4

Mg1 Mg1Mg1Mg1Mg1 Mg1 Mg1Mg1Mg1Mg1 Mg1 of a chrysotile,

SiO4 SiO4 SiO4 SiO4 Mg Si O (OH) , Mg2 Mg2 3 2 5 4 one of the Pyroxene, (Fe, Ca,Mg) Si O asbestos 2 2 6 minerals) fiber Chrysotile bundle. Bottom: (Asbestos):Mg3Si2O5(OH)4 through the fiber bundle (Ref: Grobety et al.,) http://webmineral.com/ Betechtin, Mineralogy, 1951 Nano-structured membranes have superior properties However, the physical shape of material can seriously affect its toxicity

Asbestos

Serpentine – flat sheets of atoms, harmless

Chrysotile – nano-scale tubes

One should treat these new nano-materials with caution

http://whatisasbestosis.com/risks-of-asbestos-exposure/ Nanotoxicity

‘frustrated’ phagocytosis of carbon nanotubes by peritoneal macrophages.

Asbestos nano fibres cause lung cancer

C. A. Poland et al. nature nanotechnology 3, 423 (2008)

Empa Nanosafety Research: Human macrophage exposed to Hematite-Nano band-aid coated with Ag particles (70 nm). SEM nano particles (Empa) Nanotoxicity of Au-particles

All nanoparticles within the 2–100 nm size range were found to alter signalling processes essential for basic cell functions (including cell death), 40- and 50-nm nanoparticles demonstrated the greatest effect.

W. Jiang et al. nature nanotechnology 3, 145 (2008) 10-2m 10mm

10-3m 1mm Red blood cells (~2-5μm) 10-4m 0.1mm Virus Hair (~60-120μm) (10-300nm) 10-5m 0.01mm

10-6m Infrared0.001mm, Microwave 1μm (1000nm) Bio-nano machines (<10 nm) Ag-nanoparticles 10-7m 0.1μm (100nm) (1-100 nm)

10-8m Ultraviolet 0.01μm (10nm)

10-9m 1nm

Buckyball X-ray Gold atom DNA (~1nm) 10-10m 0.1nm Courtesy Zoe (135pm) (~2nm diameter) Schnepp Colloids

 colloids, (micro-) emulsion  phase diagrams, stability  Ostwald ripening, coalescence  electrochemical double layer, zeta-potential  rheology  Aerosols

 Tyndall effect

pics_: Wikipedia

Wave length of visible light: 400 – 800 nm Can we see nano structures?

JEOL 2200FS TEM/STEM High-resolution and analytical STEM/TEM Tomography Point resolution TEM 0.23 nm Resolution STEM 0.16 nm

Ernst Karl Abbe

optics: d ~ 200 nm electron microscope d < 1 nm  d  2NA resolution limit of the microscope Nano-structure of a Hydrogen combustion catalyst

A. Fernández et al., Appl. Catal. B (2016) Scanning Probe Microscopy

 Measuring physical interaction (z)  Use it as a control parameter to map the surface

 Force (AFM)  Tunneling current (STM)  Capacity (SCAM)  Light (SNOM)  Thermal properties Tunneling current in STM

 I - + U - - surface tip + + R s vacuum metal metal   E  d F

1st images of Si (111): Binnig and Rohrer Atomic resolution of 1982 ||2 (no atoms!) Atoms at the surface of a carbon nanotube Size dependent properties

 Size and surface area effects 1 nm – 100 nm Fundamental materials properties remain the same but size, shape and surface area alter some behaviors such as work function, solubility, chemical potential, contaminate sorption

 Critical Size and Characteristic Length Scale Interesting or unusual properties because the size of the system approaches some critical length (includes quantum effects). Many characteristics of material may have normal or nearly normal behavior

 New (Non-extensive) Properties Systems not large enough to have extensive properties. Particles become effectively polymorphs of “bulk” materials and statistical homogeneity may not be valid. Size dependent properties

1020 1000 number ofatoms particle per ]  -1 

g Pd 15 2  C 10 100

1010 10

5 1 10 specific surface areaspecific [m

0.1 100 10-10 10-9 10-8 10-7 10-6 10-5 10-4 10-3 characteristic length [m] 2V contribution by surface energy   m significant below 3 nm r ratio surface atoms / bulk atoms Size dependent properties

Melting Temperature of Au Clusters Catalytic properties of Au Clusters

Au~800

T 2V  m T H r

24 Å

Ph. Buffat and J.-P. Borel, Phys. Rev. A 13, 6 1976), pp. 2287-2298

45 X. Lai, D. W. Goodman, J. Molecular Catalysis A: 162, (2 Size dependent properties

Optical properties of Au Clusters

Lycurgus cup window glass (Roman times) (Medieval times)

Illuminated from behind, the gold nanoparticle-containing dichroic glass that the cup is made from appears deep red in color. Size dependent properties

Colloidal HgTe Nanocrystals with Widely Tunable Narrow Band Gap Energies: From Telecommunications to Molecular Vibrations

Maksym V. Kovalenko ,* Erich Kaufmann , Dietmar Pachinger , Jürgen Roither , Martin Huber , Julian Stangl , Günter Hesser,Friedrich Schäffler , and Wolfgang Heiss, J. Am. Chem. Soc., 2006, 128 (11), pp 3516–3517

Metal-free Inorganic Ligands for Colloidal Nanocrystals: S2–, HS–, Se2–, HSe–, Te2–, HTe–, TeS32–, OH-, and NH2– as Surface Ligands

Angshuman Nag, Maksym V. Kovalenko, Jong-Soo Lee, Wenyong Liu, Boris Spokoyny, and Dmitri V. Talapin, J. Am. Chem. Soc., 2011, 133 (27), pp 10612–10620 Preparation of nano structures

The ‘top-down’ approach

structuring matter “Nanotechnology”

The ‘bottom-up’ approach

self-assembly “Nanochemistry”

http://www.nanoscience.at Nanostructuring on atomic length scale (Top-down)

The quantum corral reef - An academic gadget (Eigler et al. IBM) Nanostructuring by thin film technology

external transport

adsorption- homogeneous desorption nuleation heterogeneous

Cluster- surface- growth- kinetics diffusion kinetics

 physical vapor deposition (bottom-up)  chemical vapor deposition (bottom-up)  sputtering (bottom-up)  electrochemistry (bottom-up)  ion etching (top-down)  (photo-)lithography (top-down)

G. Medeiros-Ribeiro et al., Phys. Rev. B 58, 3533 (1998) Nanostructuring by ball milling (Top-down)

50 Ti(C,N)-phase 40 Ni-phase 30

20

10

0 scherrer crystallite size [nm] size crystallite scherrer 0 10203040 milling time [h]

Courtesy Nico Eigen Preparation: The ‘bottom-up’ approach

Small molecules or particles pre-designed to self assemble into larger, organised structures

e.g. surfactants Hydrophilic head group oil

oil oil water

oil oil Hydrophobic tail Spherical micelle Courtesy Zoe Sh Bottom-up approach in nature

Guanine Cytosine backbone Sugar phosphate

Adenine Thymine

Courtesy Zoe http://www.biologycorner.com/resources/DNA-colored.gif Sh Nano particles in Freshwater Biofilms

 relevant biosystem  can be grown/studied in labs

Stream biofilm inhabitants. By D. C. Sigee

http://www.iees.ch/EcoEng061/EcoEng061 Rijstenb Silver ions are bactericide

EPS reduces Ag + and stabilizes Ag NPs.

Courtesy Olga Sambalova UV-VIS on Silver-Nanoparticles

+++++++++ After 0 h ++++++++++++ 1.2 After 1 h ++++++++++++++ After 10 h ++++++++++++ 1.0 After 20 h ++++++++++ ++++++++ 0.8 discrete positive nuclei positive background

------0.6

------Absorbance + ------0.4 ------0.2 free electron cloud

400 500 600 700 ------Wavelength [nm] ------= ------ Interaction depends on ------size of the Nano particles jellium plasmon oscillation What are the scientific questions to be addressed?

 principles of existing / future technologies

physics chemistry

biology

chemical engineering What are the scientific questions to be addressed?

 principles of existing / future technologies  Underlying science / methods

computer science

surface science / microscopy

experimental methods, tools, concepts What are the scientific questions to be addressed?

 principles of existing / future technologies  Underlying science / methods  What are the problems/limits of these technologies?

applications

materials properties

picture by Zoe Schneppsafety/cost/abundance What are the scientific questions to be addressed?

 principles of existing / future technologies  Underlying science / methods  What are the problems/limits of these technologies?  future visions

artificial photosynthesis

nanocar Contents of lecture NanoChemistry

 24.02.2016Introduction  02.03.2016Measurement of Nanostructures I  09.03.2016Measurement of Nanostructures II  16.03.2016Optical Properties  23.03.2016Surface Science I  06.04.2016Surface Science II  13.04.2016Preparation of nano structures I  20.04.2016Preparation of nano structures II  27.04.2016Applications I: Catalysis  04.05.2016Applications II: Energy  11.05.2016Applications III: Wetting, Colloids  18.05.2016Theory  25.05.2016cell biology / Nanotoxicity  01.06.2016seminar talks

[email protected] Literature

 Ludovico Cademartiri and Geoffrey A. Ozin, Concepts of nanochemistry, Wiley VCH Weinheim 2009  Terence Cosgrove (Ed.), Colloid Science, principles, methods and Applications, Wiley 2010

 Lecture sheets download: http://www.chem.uzh.ch/en/study/old/documents/maste r/che834.html