Electrochemistry of Carbon Electrodes Advances in Electrochemical Sciences and Engineering Series

List of Contributors XIII

Series Editors Preface XIX

Preface XXI

1 Properties of Carbon: An Overview 1
Shengxi Huang, Johan EkWeis, Sara Costa, Martin Kalbac, and Mildred S. Dresselhaus

1.1 Overview of Properties 1

1.2 Different Forms of Carbon 2

1.2.1 Graphene 2

1.2.1.1 Optical Properties 2

1.2.1.2 Electrical Properties and Tunability 4

1.2.1.3 Spectroscopic Properties 5

1.2.2 HOPG 11

1.2.3 Carbon Nanotube 12

1.2.3.1 Structure and Electronic Properties 12

1.2.3.2 Spectroscopy and Spectroelectrochemistry of Carbon Nanotubes 14

1.2.4 Graphene Nanoribbon 18

1.2.5 Diamond 20

1.2.6 Porous Carbon 20

1.3 Outlook 21

References 21

2 Electrochemistry at Highly Oriented Pyrolytic Graphite (HOPG): Toward a New Perspective 31
Aleix G. Güell, Sze-yin Tan, Patrick R. Unwin, and Guohui Zhang

2.1 Introduction 31

2.2 Structure and Electronic Properties of HOPG 33

2.2.1 Structure and Formation 33

2.2.2 Electronic Properties 39

2.2.3 Implications for Electrochemical Studies 44

2.3 Formative Studies of HOPG Electrochemistry 45

2.3.1 Early Macroscopic Voltammetric Measurements and Correlations 45

2.3.2 Macroscopic Voltammetry and Modeling 49

2.3.3 Alternating Current (AC) Voltammetric Methods 50

2.3.4 Critical Comparison of Macroscopic Data 50

2.4 Microscopic Views of Electrochemistry at HOPG 53

2.4.1 Outer-Sphere Redox Systems 53

2.4.1.1 Scanning Micropipette Contact Method 53

2.4.1.2 Nafion Film-Covered HOPG 55

2.4.1.3 Scanning Electrochemical Cell Microscopy (SECCM) 56

2.4.1.4 Scanning Electrochemical Microscopy (SECM) 60

2.4.1.5 SECM–AFM Studies 61

2.4.1.6 Recent Macroscopic Studies 62

2.4.2 Complex Multistep Reactions: Neurotransmitter Oxidation 64

2.4.3 Adsorbed Systems 68

2.4.4 Diazonium Functionalization of HOPG 71

2.5 Conclusions 73

Acknowledgments 75

References 75

3 Electrochemistry in One Dimension: Applications of Carbon Nanotubes 83
Emiliano N. Primo, Fabiana Gutiérrez, Mar´©¥a D. Rubianes, Nancy F. Ferreyra, Marcela C. Rodr´©¥guez, Mar´©¥a. L. Pedano, Aurelien Gasnier, Alejandro Gutierrez, Marcos Egu´©¥laz, Pablo Dalmasso, Guillermina Luque, Soledad Bollo, Concepción Parrado, and Gustavo A. Rivas

3.1 Carbon Nanotubes: General Considerations 83

3.2 Structure and Synthesis of CNTs 84

3.3 Structure of CNTs versus Electrochemical Properties 86

3.4 Strategies for the Preparation of Carbon Nanotube-Based Electrodes 89

3.4.1 Functionalization 89

3.4.1.1 Covalent Functionalization 90

3.4.1.2 Noncovalent Functionalization 90

3.4.2 Preparation of Carbon Nanotube Paste Electrodes Using Different Binders 106

3.4.2.1 Screen-Printed Electrodes (SPE) 108

3.5 ProspectiveWork 108

References 109

4 Electrochemistry of Graphene 121
Hollie V. Patten, Mat¢§ej Velick´y, and Robert A.W. Dryfe

4.1 Overview of Graphene Properties 121

4.2 Preparation of Graphene 123

4.2.1 Top-Down Fabrication of Graphene 123

4.2.2 “Bottom-Up” Routes to Graphene Production 128

4.3 Capacitance of Graphene Electrodes 130

4.4 Electron Transfer Kinetics at Graphene Electrodes 137

4.4.1 Modification and Doping of Graphene for Applications in Electrocatalysis 149

4.5 Conclusion and Future Directions 151

Abbreviations 152

Symbols 152

References 153

5 The Use of Conducting Diamond in Electrochemistry 163
Julie V. Macpherson

5.1 Introduction 163

5.1.1 Boron-Doped Diamond: Electrical Properties 164

5.1.2 Growth of Synthetic Boron-Doped Diamond for Electrochemical Applications 166

5.1.2.1 High-Pressure High-Temperature (HPHT) Growth 166

5.1.2.2 Chemical Vapor Deposition Growth 167

5.2 Electrode Geometries and Arrangements 170

5.2.1 Characterization of BDD Electrochemical and Material Properties 174

5.2.1.1 Assessment of Surface Morphology 174

5.2.1.2 Extended SolventWindow and Low Capacitance 175

5.2.1.3 Raman Interrogation of sp2/sp3 Ratio in BDD 177

5.2.1.4 Outer-Sphere Redox Species Characterization 180

5.3 Effect of Surface Termination on the Electrochemical Response of BDD 182

5.3.1 Inner-Sphere Versus Outer-Sphere Electron Transfer Mechanisms 182

5.3.2 Hydrogen- and Oxygen-Terminated Diamond 183

5.3.2.1 Heterogeneous Electron Transfer Kinetics at Hydrogen- Versus Oxygen-Terminated Electrodes 186

5.4 Polycrystalline Versus Single-Crystal Electrochemistry 190

5.4.1 Electrochemical Imaging of Polycrystalline BDD 191

5.4.2 Single-Crystal BDD Electrochemistry 193

5.5 Imparting Catalytic Activity on BDD 195

5.5.1 Metal Nanoparticle-Coated BDD Electrodes 195

5.5.2 Ion Implantation 197

5.6 Chemical Functionalization of BDD Electrodes 197

5.7 Electroanalytical Applications of BDD 199

5.8 Conclusions 201

Acknowledgments 202

References 202

6 Modification of Carbon Electrode Surfaces 211
Muhammad Tanzirul Alam and J. Justin Gooding

6.1 Introduction 211

6.2 Covalent Modification 212

6.2.1 Reduction of Diazonium Cation 212

6.2.2 Oxidation of Amine 220

6.2.3 Oxidation of Carboxylate 223

6.2.4 Oxidation of Alcohol 225

6.2.5 Hydrogenation and Halogenation of Carbon 226

6.3 Noncovalent Modification 228

6.3.1 π–π Stacking 228

6.3.2 Surfactant 231

6.4 Future Directions 234

Acknowledgments 235

References 235

7 Carbon Materials in Low-Temperature Polymer Electrolyte Membrane Fuel Cells 241
Michael Bron and Christina Roth

7.1 Introduction 241

7.1.1 Brief History of the Most Prominent Carbon Materials Applied in Fuel Cell Research 242

7.1.2 Carbon Characterization 246

7.1.2.1 Raman Spectroscopy 247

7.1.2.2 Small-Angle Scattering Techniques 249

7.1.2.3 Surface Chemistry by X-ray Photoelectron Spectroscopy (XPS) and Near-Edge X-ray Absorption Spectroscopy Fine Structure (NEXAFS) 249

7.1.2.4 Other Methods and In situ Studies 251

7.2 Carbon as Support Material in Fuel Cell Electrocatalysts 251

7.2.1 Carbon Blacks 254

7.2.2 CNTs and Graphene 255

7.2.3 (Ordered)Mesoporous Carbons 257

7.2.4 Graphitization as a Means to Fight Carbon Corrosion 258

7.3 Carbon as Catalytically Active Component in Fuel Cells 259

7.3.1 ORR Activity of Carbons 259

7.3.2 N-Doped Carbons and Functionalized CNTs 260

7.3.3 Modification of Carbon Black and Other Carbon Materials 261

7.3.3.1 CNT-Based Materials 262

7.3.3.2 Graphene 262

7.3.3.3 Nanostructured Carbon Grown over Metal Catalysts 262

7.4 Carbon as Structure-Forming Element in Porous Fuel Cell Electrodes 263

7.4.1 How the Support Material Affects the Electrode Structure 264

7.4.2 How the Chosen Fabrication Step Affects the Electrode Structure 266

7.4.3 How Electrode Structuring Holds Promise to Improve Electrode Performance 267

7.4.4 Classical Electrode Designs 268

7.4.5 Advanced Designs 268

7.4.5.1 Horizontal Structuring by LbL 269

7.4.5.2 Nanostructured Electrodes 270

7.4.6 Novel Concepts 270

7.4.6.1 Electrospinning in Fuel Cell Technology 271

7.4.6.2 “Self-Assembly” by Pickering Emulsions 272

7.5 Summary and Outlook 274

Acknowledgments 275

References 275

8 Electrochemical Capacitors Based on Carbon Electrodes in Aqueous Electrolytes 285
El¢«zbieta Fr¸ackowiak, Paula Ratajczak, and François Béguin

8.1 Introduction 285

8.2 Fundamentals on Carbon/Carbon Electrical Double-Layer Capacitors 286

8.3 Carbons and Electrolytes for Electrical Double-Layer Capacitors 290

8.3.1 Electrical Double-Layer Capacitors Based on Carbon Electrodes 290

8.3.2 Electrolytes for Electrical Double-Layer Capacitors 295

8.4 Attractive Electrochemical Capacitors in Aqueous Solutions 296

8.4.1 Extension of StabilityWindow in Neutral Aqueous Electrolytes 296

8.4.2 Determination of Cell Potential Stability Limits by Floating 300

8.4.3 Capacitance Enhancement through Faradic Reactions at the Carbon–Electrolyte Interface in Aqueous Media 305

8.5 Conclusions and Perspectives 308

References 309

9 Carbon Electrodes in Electrochemical Technology 313
Derek Pletcher

9.1 Introduction 313

9.2 Comments on the Carbons Met in Electrochemical Technology 314

9.3 Manufacture of Chemicals 315

9.3.1 The Chlor-Alkali Industry 316

9.3.2 Aluminum Extraction 317

9.3.3 The Extraction of Group 1 and 2 Metals 318

9.3.4 Fluorine Generation 318

9.3.5 Ozone Generation 319

9.3.6 Hydrogen Peroxide 322

9.3.7 Other Strong Oxidizing Agents 323

9.3.8 Organic Products 323

9.4 Water and Effluent Treatment 327

9.4.1 The Removal of Organics 328

9.4.1.1 Boron-Doped Diamond 328

9.4.1.2 Hydrogen Peroxide Chemistry 329

9.4.1.3 Other Technologies 329

9.4.2 The Removal of Inorganics 330

9.5 Flow Batteries 331

References 332

10 Carbon Electrodes in Molecular Electronics 339
Adam Johan Bergren and Oleksii Ivashenko

10.1 Introduction 339

10.2 Fabrication 344

10.3 Novel Allotropes of Carbon in Molecular Electronics 350

10.3.1 Graphene 350

10.3.1.1 Electrochemistry of Graphene (see also Chapter 4) 350

10.3.1.2 Graphene in Molecular Electronics 351

10.3.2 Carbon Nanotubes 355

10.3.2.1 Electrochemistry of CNT Electrodes 357

10.3.2.2 Electronic Properties of CNTs 357

10.3.2.3 CNT-Based Electronic Devices 357

10.4 Charge Transport 360

10.4.1 Charge Transport Depends on the System 365

10.4.2 Mechanism Transitions 367

10.5 Conclusions and Prospects 367

Acknowledgments 368

References 368

11 Carbon Paste Electrodes 379
Ivan Švancara and Kurt Kalcher

11.1 Introduction: Carbon Paste Electrodes–The State of the Art 379

11.2 Carbon Paste as the Electrode Material 380

11.2.1 Basic Considerations and Classification 380

11.2.2 Characterization of Two Main Carbon Paste Components 384

11.2.2.1 Carbonaceous Moiety 384

11.2.2.2 Binder/Pasting Liquid Moiety 386

11.2.3 Physicochemical and Electrochemical Characterization of Carbon Pastes and the Respective Carbon Paste Electrodes 387

11.2.3.1 A Few Notes to the Preparation of Common Carbon Paste Mixtures 387

11.2.3.2 Typical Properties and Behavior of Traditional Carbon Paste (Electrode) 388

11.2.3.3 Specific Features of New Types of Two-Component Carbon Pastes 391

11.2.4 Survey of Applications of Two-Component and Unmodified Carbon Pastes 394

11.2.5 Current Trends in Using Carbon Pastes and Some Future Prospects 398

11.3 Modified Carbon Paste Electrodes 399

11.3.1 Modification–How to Alter the Electrode Properties in an IntentionalWay 399

11.3.2 Modification Processes 400

11.3.3 Types of Modifiers 401

11.3.4 Carbon Paste Biosensors 406

11.3.5 Applications of CMCPEs and CP-Biosensors in Surveys, Facts, and Numbers 408

11.4 Latest Achievements in Electroanalysis with CMCPEs and CP-Biosensors and Perspectives for the Future 412

References 413

12 Screen-Printed Carbon Electrodes 425
Stephen Fletcher

12.1 Introduction 425

12.2 Conductivity of Composites 426

12.3 Carbon Polymorphs 427

12.4 Oxygen Functionalities 427

12.5 Activated Carbons 428

12.6 Binder–Solvent Combinations 429

12.7 PVDF Properties 430

12.8 PVDF Solubility 432

12.9 Flexible Substrates 433

12.10 Screen Printing Process 434

12.11 Screen Printing Materials 435

12.12 Ink Flow 436

12.13 SubstrateWetting 436

12.14 Commercial Ink Additives 437

12.15 Binder Percentage 438

12.16 Multilayered Electrodes 438

12.17 IR Drop 439

12.18 Areal Capacitance 439

12.19 Equivalent Circuit 440

References 441

Index 445

Richard C. Alkire is Professor Emeritus of Chemical & Biomolecular Engineering Charles and Dorothy Prizer Chair at the University of Illinois, Urbana, USA. He obtained his degrees at Lafayette College and University of California at Berkeley. He has received numerous prizes, including Vittorio de Nora Award and Lifetime National Associate award from National Academy.

Philip N. Bartlett is Head of the Electrochemistry Section, Deputy Head of Chemistry for Strategy, and Associate Dean for Enterprise in the Faculty of Natural and Environmental Sciences at the University of Southampton. He received his PhD from Imperial College London and was a Lecturer at the University of Warwick and a Professor for Physical Chemistry at the University of Bath, before moving to his current position. His research interests include bioelectrochemistry, nanostructured materials, and chemical sensors.

Jacek Lipkowski is Professor at the Department of Chemistry and Biochemistry at the University of Guelph, Canada. His research interests focus on surface analysis and interfacial electrochemistry. He has authored over 120 publications and is a member of several societies, including a Fellow of the International Society of Electrochemistry.