Interfacial Phenomena in Electrocatalysis

by Vayenas, Constantinos G.

• ISBN13: 9781441955791
• ISBN10: 1441955798
• Format: Hardcover
• Copyright: 2011-04-06
• Publisher: Springer Verlag

Summary

This volume analyzes and summarizes recent developments and breakthroughs in several key interfacial electrochemical systems in fuel cell electrocatatalysis. The chapters are written by internationally recognized experts or rising stars in electrocatatalysis addressing both the fundamental and practical aspects of several emerging key electrochemical technologies.

Table of Contents

Tempera Ture Effects on Platinum Single-Crystal/Aqueous Solution Interphases. Combining Gibbs Thermodynamics with Laser-Pulsed Experiments
Introduction	p. 1
Analysis of Temperature Effects Based on the Use of an Isotherm	p. 5
Method of Analysis Employing a Generalized Isotherm	p. 6
Application to Hydrogen and Hydroxyl Adsorption on Pt(111)	p. 14
Review of Experimental Results on Platinum Single-Crystals	p. 19
Gibbs Thermodynamic Equations Describing Temperature Effects in the Presence and Absence of Charge-Transfer Processes	p. 21
Analysis of Temperature Effects Based on Gibbs Thermodynamics	p. 28
Entropy of Formation of the Interphase of Pt(111) in 0.1 M HClO4 Solution	p. 29
Entropy of Formation of the Double-Layer of Pt(111) in 0.1 M HClO4 Solution	p. 33
Entropy of Formation of the Interfacial Water Network on Pt(111) in 0.1 M HClO4 Solution	p. 40
Absolute Molar Entropy of Hydrogen and OH on Pt(111)	p. 43
Comparison with Results from the Application of a Generalized Isotherm	p. 48
Water Reorientation on Single-Crystal Electrodes from Nanosecond Laser-Pulsed Experiments. Potential of Maximum Entropy of Double-Layer Formation	p. 50
Fundamentals of the Laser-Induced Temperature Jump Method	p. 52
Interpretation of the Laser-Pulsed Measurements	p. 58
Pt(111), Pt(100) and Pt(110)	p. 60
Pt(111) Stepped Surfaces	p. 71
Adatom Modified Surfaces	p. 76
Conclusions	p. 82
Acknowledgments	p. 83
Glossary	p. 83
Evaluation of the Thermodiffusion Potential of Some Commonly Used Solutions	p. 86
Thermodynamic Method for the Evaluation of the Hydrogen and OH Surface Concentrations and the Double-Layer Capacity, for Platinum Electrodes in Mixed HClO4 and KClO4 Solutions	p. 88
Statistical Mechanics Derivation of Selected Thermodynamic Properties of Model Adsorption Processes	p. 93
Laser Heating	p. 97
Laser-Induced Transients with First-Order Kinetics	p. 102
References	p. 103
Surface Thermodynamics of Metal/Solution Interface: The Untapped Resources
Introductory Remarks	p. 107
Prehistory and Visible Horizon	p. 109
A Breakthrough: Frumkin-Petrii Surface Thermodynamics	p. 112
Rarity: Equilibrium Techniques to Study Adsorption	p. 112
True Double Layer Capacity	p. 116
Potentials of Zero Charge: General Trends	p. 120
Single Crystals and Old Platinum Electrochemistry Try to Meet Half-Way	p. 128
From Poorly to Well-Defined Surfaces	p. 128
Potentials of Zero Charge - Occasion to Draw Together	p. 129
From Well-Defined Surfaces to More and Less Defined Materials	p. 131
Adsorption of Anions	p. 133
Adsorption Isotherms	p. 137
The First Step towards True Charge Transfer	p. 139
Realistic and Visionary Dreams	p. 144
Concluding Remarks	p. 148
Acknowledgements	p. 149
References	p. 151
XAS Investigations of Pem Fuel Cells
Introduction	p. 159
Relationship of XAS to Other Surface Science and in Situ Techniques	p. 164
Data Analysis: ¿¿ XANES, FEFF Calculations, and EXAFS	p. 168
¿¿ XANES Technique	p. 168
Methodology	p. 168
Characteristic ¿¿ Signatures	p. 173
Methodology for EXAFS Technique	p. 181
Results Illustrating the Interplay between Cluster Morphology and Adsorbate Coverage	p. 186
Mechanisms for Enhanced CO Tolerance in Pt-M Catalysts	p. 186
PtM Catalysts in 0.3 M Methanol	p. 187
Operando Fuel Cell Studies: Hydrogen Oxidation in 100 ppm CO	p. 191
Conclusions	p. 195
References	p. 197
Palladium-Based Electrocatalysts for Alcohol Oxidation in Direct Alcohol Fuel Cells
Introduction	p. 203
Synthetic Procedures to Pd-Based Electrocatalysts for Alcohol Oxidation	p. 205
Alcohol Oxidation on Pd-Based Catalysts	p. 215
Electrochemical Studies in Half Cell	p. 216
Direct Alcohol Fuel Cell: Passive Systems	p. 233
Direct Alcohol Fuel Cell: Active Systems	p. 240
Mechanistic Studies of Alcohol Oxidation on Pd-Electrodes in Alkaline Media	p. 245
Conclusions	p. 251
References	p. 251
Structure and Reactivity of Transition Metal Chalcogenides Toward the Molecular Oxygen Reduction Reaction
Introduction and Scope	p. 255
Transition Metal Chalcogenides for Electrocatalysis	p. 257
Metal Abundance, Economic Impact and Environmental Issues	p. 257
Why Chalcogenides?	p. 258
Chemistry: Formation of High Nuclearity Complexes	p. 259
The Design of Molecular Complexes	p. 260
Genesis of a Catalyst: Rux Sey	p. 261
New Trends in Materials Research	p. 266
The Oxygen Reduction Reaction (ORR)	p. 268
The ORR Activity on Selected Cases	p. 270
Why Tolerance is Required?	p. 274
The Chemical and Thermal Stability of Highly Selective Chalcogenide Materials	p. 278
The Interfacial Dynamics at the Cathode	p. 281
The Role of Chalcogenide in Photoelectrocatalysis	p. 284
The Influence of Semiconducting Substrates on the Charge Transfer	p. 284
Electrochemistry in Solution	p. 286
Impact in Depollution of Water	p. 290
Conclusions and Outlook	p. 291
Acknowledgements	p. 293
References	p. 293
Materials, Proton Conductivity and Electrocatalysis in High-Temperature Pem Fuel Cells
Introduction: Fuel Cell Technologies	p. 301
Polymer Electrolyte Membrane Fuel Cells (PEMFC)	p. 302
Low-Temperature NAFION Based PEMFC	p. 302
High Temperature PEMFCs (HT-PEMFCs)	p. 304
General Characteristics of a HT PEMFC	p. 305
Polymer Electrolytes for HT PEMFCs	p. 306
Polybenzimidazole Based High Temperature Polymer Electrolytes	p. 306
Polybenzimidazole (PBI)	p. 306
AB-PBI	p. 312
Pyridine-Based Polybenzimidazoles (PPBI)	p. 313
PBI Polymer Blends	p. 315
PBI/SPSF Blends	p. 315
PBI/PPy(x)coPSF Blends	p. 317
Pyridine-Based Aromatic Polyethers	p. 321
Synthesis and Characterization	p. 321
Impregnation with Phosphoric Acid	p. 325
Fuel Cell Performance with Pyridine Containing Aromatic Polyethers	p. 331
The Effect of Steam on the Physicochemical and Electrochemical Properties of the Membranes	p. 331
Gas and Water Permeability	p. 331
Steam Permeability through the Polymer Electrolyte: Hydration of the PBI/PPy(50)coPSF Membrane	p. 333
Steam Effect on Cell Performance	p. 340
Steam Effect on Conductivity	p. 343
Proton Conduction	p. 348
The Electrochemical Interface	p. 351
Electrocatalytic Performance	p. 351
The Effect of Water Vapors on the Structure of the Electrochemical Interface	p. 354
Effect of Water Vapor on the Promotion of the H2 Oxidation Reaction (HOR)	p. 356
The Electrokinetics of the Oxygen Reduction Reaction	p. 358
Degradation Issues of the Electrocatalytic Layer	p. 361
Conclusions	p. 362
References	p. 363
Index	p. 369
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