Modern Aspects of Electrochemistry

by Vayenas, C. G.; Conway, Brian E.; White, Ralph E.

• ISBN13: 9780306474927
• ISBN10: 0306474921
• Format: Hardcover
• Copyright: 2003-03-01
• Publisher: Springer Verlag

Summary

Topics in Number 36 include: *Electrochemical nuclear magnetic resonance (EC-NMR). This powerful non-invasive technique brings new insights to both fundamental and practical key aspects of electrocatalysis, including the design of better anodes for PEM fuel cells. *The recent impressive advances in the use of rigorous ab initio quantum chemical calculations in electrochemistry. This lucid chapter is addressed to all electrochemists, including those with very little prior exposure to quantum chemistry, and demonstrates the usefulness of ab initio calculations, including density functional theory (DFT) methods, to understand several key aspects of fuel cell electrocatalysis at the molecular level. *The most important macroscopic and statistical thermodynamic models developed to describe adsorption phenomena on electrodes, including the current state of the art adsorption isotherms, which are both rigorous, and in good agreement with experiment. *Electrochemical promotion i.e., the use of electrochemistry to activate and in situ tune the catalytic activity and selectivity of metal and metal oxide catalysts interfaced with solid electrolytes. *Lithium transport through transition metal oxides and carbonaceous materials, which is of paramount importance in rechargeable lithium batteries.

Table of Contents

Nanoparticle Surfaces Studied by Electrochemical NMR
P. K. Babu
E. Oldfield
A. Wieckowski
Introduction	1	(3)
Experimental	4	(1)
Results and Discussion	5	(12)
Selected Topics in 195Pt-NMR	5	(2)
Other Pt Nanoparticles (Unsupported and Supported)	7	(2)
Correlation Between the 195Pt NMR Shift and Adsorbates Electronegativity	9	(5)
Spatially-Resolved Oscillation of the Ef-LDOS in a Pt Catalyst	14	(3)
13C NMR at the Electrochemical Interface	17	(23)
13C NMR Knight Shift	17	(1)
EC-NMR Under Potential Control	18	(2)
Correlation of NMR to FTIR Data	20	(2)
Correlation Between Clean Surface Ef-LDOS of Metals and the Adsorbate Knight Shift	22	(3)
NMR Comparison of CO Adsorbed on Pt-Black from Different Sources	25	(2)
Effect of Surface Charge on the Chemisorption Bond: CO Chemisorption on Pd	27	(2)
Pt Electrodes Modified by Ruthenium: A Study in Tolerance	29	(8)
EC-NMR of Pt/Ru Alloy Nanoparticles	37	(3)
Summary and Conclusions	40	(11)
Appendix	42	(6)
References	48	(3)
Ab Initio Quantum-Chemical Calculations in Electrochemistry
Marc T. M. Koper
Introduction	51	(3)
Ab Initio Quantum Chemistry	54	(10)
General Aspects of Quantum Chemistry and Electronic Structure Calculations	54	(2)
Wave-Function-Based Methods	56	(1)
Density Functional Theory Methods	57	(3)
Basis Sets and Effective Potentials	60	(1)
Structure, Energetics, and Vibrational Frequencies	61	(1)
Methods of Analysis	61	(2)
Ab Initio Molecular Dynamics	63	(1)
Selected Applications	64	(61)
Clusters and Slabs	64	(1)
How to Model the Electrode Potential	65	(2)
Chemisorption of Halogens and Halides	67	(11)
Chemisorption of Carbon Monoxide on Metals and Alloys	78	(10)
Field Dependent Chemisorption and the Interfacial Stark Effect: General Relationships	88	(10)
Field-Dependent Chemisorption of Carbon Monoxide	98	(8)
Chemisorption of Water and Water Dissociation Products	106	(9)
Ab Initio Approaches to Modeling Electrode Reactions	115	(10)
Outlook	125	(6)
References	127	(4)
Macroscopic and Molecular Models of Adsorption Phenomena on Electrode Surfaces
P. Nikitas
Introduction	131	(1)
Features of Electrosorption and Factors Affecting Them	132	(4)
Macroscopic Models	136	(4)
PC Approach	136	(2)
STE Approach	138	(2)
Molecular Models	140	(13)
Guidealli's Approach	140	(5)
Models Based on the LBS Approach	145	(8)
Complicated Adsorption Phenomena	153	(18)
Co-Adsorption and Reorientation	153	(8)
Polylayer Formation	161	(3)
Surface Segregation	164	(2)
Phase Transitions	166	(5)
Polarization Catastrophe and Other Artifacts	171	(6)
The Role of the Metal Electrode---The Case of Solid Electrodes	177	(5)
Computer Simulation	182	(2)
Conclusions	184	(7)
References	185	(6)
Electrochemical Promotion of Catalysis
Gyorgy Foti
Ivan Bolzonella
Christos Comninellis
Introduction	191	(2)
The Phenomenon of Electrochemical Promotion	193	(14)
Description of a Typical Electrochemical Promotion Experiment	194	(3)
The Mechanism of Electrochemical Promotion	197	(6)
Promotional Transients	203	(4)
Fundamental Studies of Electrochemical Promotion	207	(29)
Catalytic Model Systems	207	(2)
Experimental Aspects	209	(3)
Electrochemical Characterization of the Single-Pellet Cell	212	(4)
Cyclic Voltammetry	216	(3)
Fast-Galvanostatic Transients	219	(5)
Permanent Electrochemical Promotion	224	(4)
Electrochemical Activation of a Catalyst	228	(2)
Electrochemical Promotion and Catalyst-Support Interactions	230	(3)
Work Function Measurements	233	(3)
Cell Development for Electrochemical Promotion	236	(14)
Bipolar Con guration for Electrochemical Promotion	236	(5)
Ring-Shaped Electrochemical Cell	241	(3)
Multiple-Channel Electrochemical Cell	244	(4)
Perspectives	248	(2)
Conclusions	250	(5)
References	252	(3)
Mechanisms of Lithium Transport Through Transition Metal Oxides and Carbonaceous Materials
Heon-Cheol Shin
Su-II Pyun
Introduction	255	(2)
Bird's Eye View of the Models for Current Transients in Lithium Intercalation Systems: Diffusion Controlled Lithium Transport	257	(4)
The Geometry of the Electrode Surface	259	(1)
The Growth of a New Phase in the Electrode	260	(1)
The Electric Field in the Electrode	261	(1)
General Perspective on Current Transients from Transition Metal Oxides and Graphite	261	(12)
Non-Cottrell behavior throughout the Lithium Intercalation/Deintercalation	264	(3)
Intersection of Anodic and Cathodic Current Transients	267	(1)
(Quasi-)Current Plateau	268	(5)
Depression of the Initial Current Value	273	(1)
Physical Origin of the Current Transients	273	(10)
Linear Relation Between Current and Electrode Potential	273	(5)
Comparison of Cell Resistances Determined by the Current Transient Technique and by Electrochemical Impedance Spectroscopy	278	(5)
Theoretical Description of Cell-Impedance Controlled Lithium Transport	283	(14)
Governing Equation and Boundary Condition	283	(1)
Calculation Procedure of the Cell-Impedance Controlled Current Transients	284	(2)
Theoretical Current Transients and their Comparison with Experimental Current Transients	286	(8)
Some Model Parameters Affecting the Shape and Magnitude of the Cell-Impedance Controlled Current Transients	294	(3)
Concluding Remarks	297	(6)
References	298	(5)
Index	303