Electroanalytical Methods (eBook)

Preface to the Second Edition 7
Preface to the First Edition 8
Contents 9
Contributors 14
Index of Symbols and their SI Dimensions 15
I. Roman Symbols 15
II. Greek Symbols 20
Part I Basic Electrochemistry 22
I.1 The Electrical Double Layer and Its Structure 23
1.1 Introduction 23
1.2 Double-Layer Models 25
1.3 Thickness of the Electric Double Layer 27
1.4 Recent Developments 28
References 28
I.2 Thermodynamics of Electrochemical Reactions 30
2.1 Introduction 30
2.2 The Standard Potential 30
2.3 The Formal Potential 38
2.4 Characteristic Potentials of Electroanalytical Techniques 41
I.2.4.1 Direct Current Polarography (Employing a Dropping-Mercury Electrode) 41
I.2.4.1.1 The Half-Wave Potential E1/2 41
I.2.4.1.2 Influence of Diffusion 41
I.2.4.1.3 Influence by Amalgamation 42
I.2.4.1.4 Influence by Solution Equilibria 42
I.2.4.1.5 Influence by Irreversibility of the Electrode System 44
I.2.4.2 Cyclic Voltammetry 44
I.2.4.2.1 The Peak Potentials 44
I.2.4.3 Differential Pulse Voltammetry (DPV), Alternating Current Voltammetry (ACV), and Square-Wave Voltammetry (SWV) 45
2.5 Thermodynamics of the Transfer of Ions Between Two Phases 46
2.6 Thermodynamic Data Derived from Standard and Formal Potentials 48
I.2.6.1 Data Derived from Standard Potentials 49
I.2.6.2 Data Derived from Formal Potentials 50
References 50
I.3 Kinetics of Electrochemical Reactions 51
3.1 Introduction 51
3.2 Relationship Between the Current Density and Potential Under Steady-State Conditions 52
I.3.2.1 Equilibrium 54
I.3.2.2 Rate Controlled by the Charge Transfer Step 55
I.3.2.3 Effect of Mass Transport on the Kinetics of Electrode Processes 56
I.3.2.3.1 Diffusion 56
I.3.2.3.2 Migration 60
I.3.2.3.3 Convection 61
I.3.2.4 Reversibility, Quasi-reversibility, and Irreversibility 62
I.3.2.5 Effect of the Double-Layer Structure on the Rate of the Charge Transfer Reaction 66
3.3 CurrentPotential Transients 67
I.3.3.1 Charging the Double Layer 67
I.3.3.2 Faradaic Current 69
References 71
Part II Electroanalytical Techniques 72
II.1 Cyclic Voltammetry 73
1.1 Introduction 73
II.1.1.1 Shape of Cyclic Voltammograms 76
1.2 Basic Principles 79
1.3 Effects Due to Capacitance and Resistance 87
1.4 Electrode Geometry, Size, and Convection Effects 90
1.5 Determination of Redox State and Number of Transferred Electrons 94
II.1.5.1 Chronoamperometric Test Procedure 94
II.1.5.2 Method Based on Cyclic Voltammetry 94
II.1.5.3 Methods Based on Steady-State Techniques 95
1.6 Heterogeneous Kinetics 97
1.7 Homogeneous Kinetics 103
II.1.7.1 The EC Process 104
II.1.7.2 The EC Process 107
II.1.7.3 The CE Process 108
II.1.7.4 The ECE Process 110
II.1.7.5 The ECE Process 113
II.1.7.6 Square Schemes and More Complex Reaction Schemes 113
1.8 Multi-phase Systems 114
References 118
II.2 Pulse Voltammetry 123
2.1 Introduction 123
2.2 Staircase Voltammetry 126
II.2.2.1 Equivalence of Staircase and Linear Scan Voltammetries 127
2.3 Normal Pulse Voltammetry 127
II.2.3.1 Influence of Adsorption 130
2.4 Reverse Pulse Voltammetry 131
2.5 Differential Pulse Voltammetry 133
References 135
II.3 Square-Wave Voltammetry 136
3.1 Introduction 136
3.2 Simple Reactions on Stationary Planar Electrodes 137
3.3 Simple Reactions on Stationary Spherical Electrodes and Microelectrodes 142
3.4 Reactions of Amalgam-Forming Metals on Thin Mercury Film Electrodes 143
3.5 Electrode Reactions Complicated by Adsorption of the Reactant and Product 144
3.6 Applications of Square-Wave Voltammetry 149
3.7 Appendix 150
References 158
II.4 Chronocoulometry 161
4.1 Introduction 161
4.2 Fundamental Theoretical Considerations 162
4.3 Practical Problems 164
4.4 Double-Step Chronocoulometry 166
4.5 Effect of Heterogeneous Kinetics on Chronocoulometric Responses 169
References 171
II.5 Electrochemical Impedance Spectroscopy 173
5.1 Introduction 173
5.2 Definitions, Basic Relations, the KramersKronig Transforms 173
5.3 Measuring Techniques 175
5.4 Representation of the Impedance Data 178
5.5 Equivalent Circuits 178
5.6 The Constant Phase Element 178
5.7 Complex Non-Linear Regression Least-Squares (CNRLS) for the Analysis of Impedance Data 179
5.8 Commercial Computer Programs for Modelling of Impedance Data 180
5.9 Charge Transfer at the Electrode the Randles Model 180
5.10 Semi-infinite Hemispherical Diffusion for Faradaic Processes 184
5.11 Diffusion of Particles in Finite-Length Regions the Finite Warburg Impedance 185
5.12 Homogeneous or Heterogeneous Chemical Reaction as Rate-Determining Step 186
5.13 Porous Electrodes 187
5.14 Semiconductor Electrodes 187
5.15 Kinetics of Non-Faradaic Electrode Processes 188
5.16 References to Relevant Fields of Applications of EIS 190
References 190
II.6 UV/Vis/NIR Spectroelectrochemistry 192
6.1 Introduction Why Couple Techniques? 192
6.2 Flowing Versus Stagnant Systems Achieving Spatial, Temporal, and Mechanistic Resolution 195
II.6.2.1 Steady-State or Transient Techniques 195
II.6.2.2 Cell Geometry and Experimental Design Considerations 197
II.6.2.3 Time-Scale Considerations 198
II.6.2.4 Spatial and Mechanistic Resolution 199
6.3 UV/Vis/NIR Spectroelectrochemical Techniques 200
II.6.3.1 Spectroelectrochemistry in Transmission Mode 200
II.6.3.2 Spectroelectrochemistry in Reflection Mode 210
References 211
II.7 Stripping Voltammetry 214
7.1 Introduction 214
7.2 Overview of Preconcentration Methods 215
II.7.2.1 Metal Deposition on Solid Electrodes 216
II.7.2.2 Metal Deposition on Mercury Electrodes 219
II.7.2.2.1 Pseudopolarography 221
II.7.2.3 Deposition of Sparingly Soluble Salts on Electrodes 222
II.7.2.4 Adsorptive Preconcentration 224
II.7.2.5 Preconcentration by Surface Complexation 228
7.3 Stripping Voltammetry at Two Immiscible Liquid Electrolyte Solutions 228
7.4 General Features of Stripping Voltammetry 229
References 231
II.8 Electrochemical Studies of Solid Compounds and Materials 235
8.1 Introduction 235
8.2 Experimental 235
II.8.2.1 Electrodes and Electrode Preparation 235
II.8.2.1.1 Carbon Electrodes 236
II.8.2.1.2 Metal Electrodes 237
II.8.2.1.3 Other Electrodes 238
II.8.2.2 Sample Preparation 238
II.8.2.3 Experimental Setup 239
II.8.2.4 Strategy 239
II.8.2.5 What Compounds and Materials Can Be Studied? 240
8.3 Electrochemical Methods 240
II.8.3.1 Phase Identifications and Quantitative Analysis of Solids 240
II.8.3.2 Studies of the Electrochemical Behavior of Solid Materials 242
8.4 Combined Methods 244
II.8.4.1 Ex Situ Methods 244
II.8.4.2 In Situ Methods 245
References 245
II.9 Potentiometry 248
9.1 Introduction 248
9.2 Cell Voltage 248
9.3 Indicator Electrodes and Their Potentials 249
II.9.3.1 Redox Electrodes 249
II.9.3.2 Metal Electrodes or Electrodes of the First Kind 253
II.9.3.3 Electrodes of the Second Kind 254
II.9.3.4 Membrane Electrodes 255
II.9.3.4.1 Semipermeable Membrane Without Inner Diffusion Potential 256
II.9.3.4.2 Potential Difference at a Glass Electrode 257
II.9.3.4.3 Solid-Contact Inner Reference Systems 262
9.4 Interferences and Detection Limits in Potentiometric Measurements 262
References 266
II.10 Electrochemical Quartz Crystal Nanobalance 268
10.1 Introduction 268
10.2 Theory and Basic Principles of Operation 269
II.10.2.1 Piezoelectricity, Converse Piezoelectricity, Piezoelectric Materials, and Oscillators 269
II.10.2.2 The Quartz Crystal Nanobalance 270
II.10.2.3 The Electrochemical Quartz Crystal Nanobalance (EQCN) 271
10.3 Applications of EQCN: Selected Examples 273
II.10.3.1 Redox Transformations of [Fe(CN) 6 ] 3- /[Fe(CN) 6 ] 4- System on Gold 274
II.10.3.2 Underpotential Deposition of Hydrogen and Oxygen on Pt and Rh Surfaces and the Effect of the Electrochemical Double Layer 274
II.10.3.3 Polymer Film Electrodes: Electrodeposition and Ionic Exchange Processes 276
II.10.3.4 Microcrystals 278
II.10.3.5 Electrochemical Oscillations 280
References 280
Part III Electrodes and Electrolytes 282
III.1 Working Electrodes 283
1.1 Introduction 283
1.2 Electrode Materials 285
1.3 Electrode Geometry 290
1.4 Hydrodynamic Conditions 292
1.5 Chemically Modified Electrodes 296
References 298
III.2 Reference Electrodes 301
2.1 Introduction 301
2.2 The Standard Hydrogen Electrode 303
2.3 Electrodes of the Second Kind as Reference Electrodes 304
III.2.3.1 Mercury-Based Reference Electrodes 304
III.2.3.1.1 The Calomel Electrode 304
III.2.3.1.2 The Mercury/Mercury(I) Sulphate Electrode 306
III.2.3.1.3 The Mercury/Mercuric Oxide Electrode 306
III.2.3.2 The Silver/Silver Chloride Electrode 308
2.4 pH-Based Reference Electrodes 309
2.5 Inner Potential Standards 310
2.6 Solid-State Reference Electrodes 311
2.7 Pseudo Reference Electrodes 312
2.8 Practical Problems 313
III.2.8.1 The Electrolyte of Reference Electrodes 313
III.2.8.2 The Diaphragm 316
III.2.8.3 Refilling of the Reference Solution 317
III.2.8.4 Maintenance of Reference Electrodes 317
References 318
III.3 Electrolytes 319
3.1 Introduction 319
3.2 Ionic Transport 320
3.3 Ionic Solutions 327
III.3.3.1 Aqueous Electrolyte Solutions 333
III.3.3.1.1 Synthetic Aqueous Electrolyte Solutions 333
III.3.3.1.2 Seawater, a Natural Aqueous Electrolyte Solution 334
III.3.3.2 Nonaqueous Electrolyte Solutions 336
III.3.3.2.1 Alcohols 336
III.3.3.2.2 Acids 337
III.3.3.2.3 Amines 337
III.3.3.2.4 Ethers 338
III.3.3.2.5 Nitriles 338
III.3.3.2.6 Amides 338
III.3.3.2.7 Dimethyl Sulfoxide 339
III.3.3.2.8 Methylene Chloride 339
References 340
III.4 Experimental Setup 341
4.1 Introduction 341
4.2 The Working Electrode 341
4.3 The Reference Electrode 342
4.4 The Counter Electrode 343
4.5 Instrumental Parameters and Wiring 343
4.6 Nonaqueous Media 344
4.7 Elimination of Electrical Noise 344
References 345
Part IV Publications in Electrochemistry 346
IV.1 Seminal Publications in Electrochemistry and Electroanalysis 347
IV.2 Books on Fundamental Electrochemistry and Electroanalytical Techniques 351
Index 354