Electrochemistry of N4 Macrocyclic Metal Complexes (eBook)

Fethi Bedioui is currently at Chimie Paris Tech. Jose Zagal is currently at Universidad de Santiago de Chile.

Foreword 5
Preface 6
Contents 9
Editors and Contributors 10
1 Oxygen Electroreduction on M-N4 Macrocyclic Complexes 13
1 Introduction 13
2 ORRs on Carbon-Supported M-N4 Macrocyclic Molecules 16
2.1 Effect of Central Transition Metal Atom 19
2.2 Effect of Chelates and Peripheral Substitutes 20
2.3 Effect of Polymerization 20
2.4 Effect of Substrate Materials and Electrode Preparation 21
2.5 Effect of pH Value of Electrolyte 22
2.6 Mechanism of ORR on M-N4 Macrocyclic Complexes 22
3 ORRs on Carbon-Supported Heat-Treated M-N4 Macrocyclic Molecules 24
3.1 Effect of Heat Treatment Temperature and Duration 25
3.2 Effect of Pyrolysis Gas Atmosphere 25
3.3 Effect of Additives 30
3.4 Proposed Mechanisms for Heat Treatment 30
4 ORRs on M-N4 Macrocycle Modified Carbon Nanostructures (Nanotubes and Graphene) 31
4.1 M-N4 Macrocycle Modified CNT 31
4.2 M-N4 Macrocycle Modified Graphene 32
5 Application of DFT to Understand ORRs on M-N4 Macrocycles 34
5.1 DFT Study of O2 Adsorption on M-N4 Macrocyclic Complexes 34
5.2 DFT Study of ORR on M-N4 Macrocyclic Complexes 36
5.3 DFT Study of ORR on M-N4 Clusters Between Graphitic Pores 39
5.4 DFT Study of ORR on M-N4 Clusters Embedded in Graphene 41
6 Concluding Remarks 42
References 42
2 Heat-Treated Non-precious Metal Catalysts for Oxygen Reduction 52
1 Introduction 52
1.1 Polymer Electrolyte Fuel Cells—The Cathode Challenge 52
1.2 Performance Requirements 53
2 Synthesis Path 54
2.1 Precursors 54
2.1.1 Nitrogen–Carbon Precursors 54
2.1.2 Transition Metal Precursors 56
2.1.3 Effect of Carbon Support 60
2.2 Effect of Heating Temperature 61
3 Performance Evaluation and Catalyst Characterization Techniques 62
3.1 Electrochemical Cell Testing 62
3.1.1 Electrochemical Cell Set-up 63
3.1.2 RDE/RRDE Measurements 63
3.2 Fuel Cell Testing 66
3.3 Physicochemical Characterization Techniques 67
4 Catalyst Structure 69
4.1 The Active Site Debate 69
4.2 Mass Transport Facilitation 71
5 Summary 74
References 75
3 Non-noble Metal (NNM) Catalysts for Fuel Cells: Tuning the Activity by a Rational Step-by-Step Single Variable Evolution 80
1 Introduction 80
1.1 Technical Challenges 81
2 Influence of the Carbon Support in Forming Active Ensembles 89
2.1 The Use of Mesoporous Carbon (MPC) Hosting the Nitrogen–Iron Active Ensembles 90
2.2 The Use of Reduced Graphene Oxide (rGO) Hosting the Nitrogen–Iron Active Ensembles 91
2.3 The Use of Graphitic Interconnected Carbon Nano-Networks (CNN) Hosting the Nitrogen–Iron Active Ensembles 93
2.4 The Use of Polymerized Mesoporous Carbon (MPC_PPY) Hosting the Nitrogen–Iron Active Ensembles 94
2.5 The Lesson Learned from the Use of Different Types of Carbon Hosting the Nitrogen–Iron Active Ensembles 96
3 The Use of a Non-carbonaceous Support in Forming Active Ensembles 98
3.1 The Use of Non-carbonaceous Supports (SBA15 And commercial Mesoporous SiO2) Hosting the Carbon–Nitrogen–Iron Active Ensembles 98
3.2 Considerations On the Pyrolyzation Process and the Decomposition of Iron–Nitrogen–Carbon Macrocycles used as Precursor 100
4 Alternative Perspectives 102
5 Conclusions 103
Acknowledgments 104
References 105
4 Application of Scanning Electrochemical Microscopy (SECM) to Study Electrocatalysis of Oxygen Reduction by MN4-Macrocyclic Complexes 113
1 Introduction 113
1.1 Scanning Electrochemical Microscopy (SECM) 113
1.2 Instrumentation 114
1.3 Microelectrodes 115
1.3.1 Mass Transport at Microelectrodes 115
1.3.2 Current Line Distribution and Ionic Resistance of the Electrolyte 117
1.4 Modes of Operation in SECM 118
1.4.1 Feedback Mode 119
1.4.2 Generation/Collection Mode 120
1.4.3 Redox Competition Mode 121
1.4.4 Surface Patterning Mode 122
1.5 Influence of the Sample Surface Topography 123
1.5.1 Intermittent Contact in SECM 123
1.5.2 Soft Microelectrodes in SECM 124
1.5.3 Combination of Atomic Force Microscopy with Scanning Electrochemical Microscopy (AFM–SECM) 124
1.5.4 Shear force in SECM 125
1.5.5 Combination of Scanning Ion-Conductance Microscopy with Scanning Electrochemical Microscopy (SICM–SECM) 125
1.5.6 Scanning Electrochemical Cell Microscopy (SECCM) 126
2 Study of the Oxygen Reduction Reaction (ORR) Using SECM 127
2.1 Electrocatalysis of Oxygen Reduction 127
2.1.1 Visualization of Oxygen Reduction Using SECM 129
2.1.2 High-Throughput Screening of ORR Catalysts Using SECM 131
2.1.3 Quantification of Hydrogen Peroxide 134
2.2 Evaluation of the Electrocatalytic Activity of Single Particles 137
2.2.1 Single Particle Attached to a Nanoelectrode 137
2.2.2 Electrocatalytic Current Amplification via Single Nanoparticle Collisions 138
2.2.3 Evaluation of ORR at Single Particles Using SECM 138
2.3 Variable Temperature SECM 140
3 Application of SECM to Study Oxygen Reduction by MN4-Macrocyclic Complexes 142
4 Conclusions and Outlook 145
References 146
5 Theoretical Aspects of the Reactivity of MN4 Macrocyclics in Electrochemical Reactions 152
1 Introduction 152
2 Theoretical and Computational Details 156
3 Results and Discussion 158
3.1 Self-assembled Metallophthalocyanines Complexes on a Gold Clusters 158
3.2 Self-assembled Metallophthalocyanines Complexes Anchored on a Gold Clusters for O2 Reduction 162
3.3 Electrocatalytic Activity MetalloN4-Macrocyclic Complexes of Thiocyanate 167
4 Summary and Outlook 172
Acknowledgments 172
References 173
6 Metalloporphyrins in Solar Energy Conversion 180
1 Introduction 182
1.1 Metalloporphyrins in Photovoltaics 182
1.2 Solar Cell Fundamentals 183
2 Mechanism of Organic Photovoltaics Operation 185
2.1 Thin-Film Small-Molecule and Polymer Solar Cells 185
2.2 Dye-Sensitized Solar Cells 187
2.3 Supramolecular Solar Cells 187
3 Effects of Peripheral Substituents of the Metalloporphyrin Macrocycle on the Photovoltaic Cell Performance 189
3.1 Porphyrins in Dye-Sensitized Solar Cells 190
3.1.1 The Effect of Position, Nature, and Number of Porphyrin Anchoring Peripheral Substituents on Performance of a Dye-Sensitized Solar Cell 190
3.1.2 4A- and 3AB-Type Meso-Tetraphenyl Substituted Porphyrins 196
3.1.3 3AB- and A3B-Type Meso-Tetraphenyl Substituted Porphyrins 197
3.1.4 3AB-Type Porphyrins with Heteroatomic Anchoring Groups 206
3.1.5 2A2B-Type Porphyrins 208
3.1.6 Trans-A2BC-Type Porphyrins: Strategies for Improvement of the Porphyrin Design 212
Decoupled Donor-(Bridge)-Acceptor (D-B-A) Systems 212
Mixed-Type Donor-Bridge-Acceptor Systems Bearing Coupled with Metalloporphyrin Donor or Acceptor Moiety: “Push-Bridge-Acceptor” and “Donor-Bridge-Pull” Systems 215
Trans-A2BC-Type Porphyrin ?-Conjugated with Both Donor and Acceptor Moieties: “Push–Pull” Porphyrins 219
Improvement of the YD2 and YD-o-C8 Zinc Porphyrin Design by Broadening Absorbance Wavelength Range for “Push–Pull” Porphyrins Through Modification of Their Donor and Acceptor Moieties 225
Fully Conjugated Cis-, Trans-A2BCD-, and ABCD-Type Porphyrins 233
3.1.7 Conclusions on Progress and Perspectives of Porphyrin-Sensitized Solar Cells 235
3.2 Bulk Heterojunction Solar Cells 235
3.2.1 Monomeric and Oligomeric Porphyrins in Bulk Heterojunction Solar Cells 236
3.2.2 Porphyrin Polymers in Bulk Heterojunction Solar Cells 245
3.2.3 Conclusions on the Progress of Porphyrin-Containing Bulk Heterojunction Solar Cells 256
3.3 Supramolecular Assemblies Based on Organic Donor–Acceptor Constructs 256
3.3.1 Porphyrin–Fullerene Donor–Acceptor Constructs 257
3.3.2 Porphyrin and Porphyrin–Phthalocyanine Constructs 259
3.3.3 Porphyrin–Graphene Donor–Acceptor Constructs 260
3.3.4 Conclusions on Porphyrin-Containing Supramolecular Solar Cells 261
4 Conclusion 262
Acknowledgements 262
References 263
7 Photoelectrochemical Reactions at Phthalocyanine Electrodes 272
1 Introduction 272
2 Essentials of Photoelectrochemical Reactions 273
3 Photoelectrochemical Experiments at Phthalocyanine Thin Films 275
3.1 Preparation of Thin Films 275
3.2 Semiconductor Characteristics of Solid Phthalocyanine Films 276
3.3 Position of Frontier Energy Levels in Phthalocyanines 278
3.4 Photocurrent Direction at Phthalocyanine Electrodes 279
3.5 Role of Higher Excited States 283
3.6 Reactant Adsorption 286
3.7 Surface Defects 288
3.7.1 Fermi Level Pinning 288
3.7.2 Photoelectrochemical Electrode Kinetics 290
Photocurrent Transients 290
Intensity-Modulated Photocurrent Spectroscopy (IMPS) 294
4 Sensitization of Oxide Semiconductors by Phthalocyanines 300
4.1 Sensitization of Nanoparticulate Semiconductors 300
4.2 Sensitization of Electrodeposited Semiconductor Thin Films 303
4.2.1 Electrodes Deposited in the Presence of Phthalocyanines 304
4.2.2 Sensitization by Subsequently Adsorbed Phthalocyanines 308
5 Technology Outlook 310
Acknowledgments 312
References 312
Index 324