Green reactions - like photo-, photoelectro-, and electro-catalytic reactions - offer viable technologies to solve difficult problems without significant damage to the environment. In particular, some gas-involved reactions are especially useful in the creation of liquid fuels and cost-effective products.
In Photo- and Electro-Catalytic Processes: Water Splitting, N2 Fixing, CO2 Reduction, award-winning researcher Jianmin Ma delivers a comprehensive overview of photo-, electro-, and photoelectron-catalysts in a variety of processes, including O2 reduction, CO2 reduction, N2 reduction, H2 production, water oxidation, oxygen evolution, and hydrogen evolution. The book offers detailed information on the underlying mechanisms, costs, and synthetic methods of catalysts.
Filled with authoritative and critical information on green catalytic processes that promise to answer many of our most pressing energy and environmental questions, this book also includes: - Thorough introductions to electrocatalytic oxygen reduction and evolution reactions, as well as electrocatalytic hydrogen evolution reactions - Comprehensive explorations of electrocatalytic water splitting, CO2 reduction, and N2 reduction - Practical discussions of photoelectrocatalytic H2 production, water splitting, and CO2 reduction - In-depth examinations of photoelectrochemical oxygen evolution and nitrogen reduction
Perfect for catalytic chemists and photochemists, Photo- and Electro-Catalytic Processes: Water Splitting, N2 Fixing, CO2 Reduction also belongs in the libraries of materials scientists and inorganic chemists seeking a one-stop resource on the novel aspects of photo-, electro-, and photoelectro-catalytic reactions.
Table of Contents
Preface xiii
1 Oxygen Reduction Reaction Electrocatalysts 1
Xinwen Peng and Lei Zhang
1.1 Introduction 1
1.2 Pt-Based ORR Electrocatalysts 2
1.2.1 Facet-Controlled Catalysts 2
1.2.2 Multimetallic Nanocrystals 3
1.2.2.1 Pt Alloys 3
1.2.2.2 Supported-Enhanced Catalysts 6
1.3 Transition-Metal-Based Materials 10
1.3.1 Metals and Alloys 10
1.3.2 Transition Metal Oxides/Sulfides 12
1.4 Atomically Dispersed Metal in Carbon Materials 19
1.5 Metal-Free ORR Electrocatalysts 23
1.6 Conclusion 25
References 26
2 Electrocatalytic Oxygen Evolution Reaction 35
Guanyu Liu and Joel W. Ager
2.1 Introduction 35
2.2 Bioinspiration: OER in Photosystem II 36
2.3 Fundamentals of Electrocatalytic OER 36
2.3.1 Electrode Substrate 37
2.3.2 Electrolyte 38
2.3.3 Onset Potential and Overpotential 38
2.3.4 Tafel Analysis of the Rate-Determining Step 38
2.3.5 pH Dependence: The Nernst Equation 39
2.3.6 Long-Term Stability 41
2.3.7 Other Parameters 41
2.4 Reaction Mechanisms 41
2.4.1 WNA Mechanism 42
2.4.2 I2M Mechanism 44
2.5 OER Catalysts 44
2.5.1 Molecular OER Catalysts 44
2.5.1.1 Ru- and Ir-Based Molecular Catalysts 45
2.5.1.2 Earth-Abundant Transition Metal-Based Molecular Catalysts 46
2.5.1.3 Stabilization Strategies for Molecular Catalysts 47
2.5.1.4 All-Inorganic Polyoxometalates 48
2.5.2 Heterogeneous OER Catalysts 48
2.5.2.1 Metal Oxides 48
2.5.2.2 (Oxy)Hydroxides and Double Hydroxides 54
2.5.2.3 Metal Chalcogenides 55
2.5.2.4 Metal Pnictides 57
2.5.2.5 Carbon-Based Materials 58
2.5.2.6 Crystalline Frameworks and Their Derivatives 59
2.6 Challenges for Practical Catalytic Electrodes for OER 62
2.6.1 Industrially Viable Fabrication Techniques 62
2.6.2 Gas Bubble Formation on the Surface of Electrodes 62
2.6.3 Novel Approaches Toward Catalyst Discovery 65
2.7 Conclusions 67
References 68
3 Electrochemical Hydrogen Evolution Reaction 87
Guoqiang Zhao and Wenping Sun
3.1 Introduction 87
3.2 HER Mechanism 89
3.2.1 HER Mechanism in Acid Media 89
3.2.2 HER Mechanism in Alkaline Media 93
3.3 Key Parameters for Evaluating Catalytic Activity 96
3.3.1 Overpotential 96
3.3.2 Turnover Frequency 97
3.4 PGMs-Based Electrocatalysts 98
3.4.1 PGM Alloys 99
3.4.2 PGM Heterostructured Electrocatalysts 101
3.4.3 PGM Single-Atom Electrocatalysts 106
3.5 PGM-Free Materials 108
3.5.1 2D Transition Metal Dichalcogenides 108
3.5.2 Transition Metal Phosphorus/Nitrides/Carbides 111
3.5.3 PGM-Free Heterostructured Electrocatalysts 112
3.6 Summary 117
References 118
4 Electrocatalytic Water Splitting 123
Suraj Gupta
4.1 Introduction 123
4.2 Fundamental Concepts 124
4.2.1 Electric Double Layer 124
4.2.2 Standard Electrode Potential 125
4.2.3 Overpotential 129
4.2.4 Electrode Kinetics 129
4.3 Industrial Systems for Electrocatalytic Water Splitting 133
4.3.1 Alkaline Water Electrolyzers 133
4.3.2 Proton Exchange Membrane Water Electrolyzers 135
4.3.2.1 Membrane Electrode Assembly 136
4.3.2.2 Current Collectors 137
4.3.2.3 Bipolar/Separator Plates 138
4.3.3 Zero-Gap AWE 138
4.3.4 Comparing PEMWE and AWE 139
4.3.5 Other Types of Water Electrolyzers 141
4.3.5.1 Solid Oxide Electrolyzers 141
4.3.5.2 Microbial Electrolyzers (MEs) 144
4.4 Electrocatalysts for HER and OER 145
4.5 Electrocatalytic Seawater Splitting 147
4.5.1 Demographic Analysis 147
4.5.2 Challenges in Electrocatalytic Seawater Splitting 147
4.5.3 State-of-the-Art 151
4.5.4 Prospects for Electrocatalytic Splitting of Seawater 153
4.6 Conclusions 154
References 154
5 Electrochemical Carbon Dioxide Reduction Reaction 159
Yating Zhu, Congyong Wang, Zengqiang Gao, Junjun Li, and Zhicheng Zhang
5.1 Introduction 159
5.2 Principles 160
5.2.1 The Conversion of CO2 to C1 Products 160
5.2.2 The Conversion of CO2 to Multi-Carbon Products 161
5.3 Materials for Electrochemical CO2RR 163
5.3.1 Metallic Materials 163
5.3.1.1 Transition Metallic Materials 163
5.3.1.2 Other Metallic Materials 165
5.3.2 Carbon Materials 165
5.3.2.1 Carbon Nanofibers 167
5.3.2.2 Carbon Nanotubes 167
5.3.2.3 Mesoporous Carbon 168
5.3.2.4 Graphene (Graphene Quantum Dots) 168
5.3.2.5 Diamond 170
5.3.3 Organic Framework Materials 171
5.3.3.1 Metal-Organic Frameworks 172
5.3.3.2 Covalent Organic Frameworks 176
5.4 Conclusion 178
References 180
6 Electrochemical N2 Reduction 183
Yulu Yang, Jiandong Liu, Huapin Wang, and Jianmin Ma
6.1 Introduction 183
6.2 Fundamentals of Electrocatalytic Nitrogen Reduction 184
6.3 Product Detection and Efficiency Evaluation 186
6.4 NRR Catalysts 188
6.4.1 Noble Metal Catalysts 188
6.4.1.1 Au Base Catalyst 188
6.4.1.2 Ru Base Catalyst 190
6.4.1.3 Pd Base Catalyst 191
6.4.1.4 Pt Base Catalyst 191
6.4.2 Non-noble Metal Catalyst 191
6.4.2.1 Mo Base Catalyst 194
6.4.2.2 Ni, Co and Fe Base Catalyst 197
6.4.2.3 Metal-Free Catalysts 197
6.4.3 Monatomic Catalysts 197
6.5 Conclusion and Prospects 202
References 202
7 Photoelectrochemical Water Splitting 205
Yangqin Gao, Ge Lei, Zhijie Tian, Hongying Zhu, and Lianzheng Ma
7.1 Introduction 205
7.2 Photoelectrochemical Cells 208
7.2.1 Water Splitting 209
7.2.2 Types of Photoelectrochemical Devices 209
7.2.2.1 Photoelectrolysis Cell 210
7.2.2.2 Photo-Assisted Electrolysis Cell 210
7.2.2.3 Photovoltaic Electrolysis Cell 210
7.3 Basic Concepts in Semiconductors 211
7.3.1 Electronic Properties of Semiconductors 211
7.3.2 Optical Properties of Semiconductors 218
7.3.3 Quasi Thermal Equilibrium and Quasi Fermi Level Splitting 222
7.4 General Properties of a Semiconductor/Liquid Junction 224
7.4.1 Equilibrium State at a Semiconductor/Liquid Junction 224
7.4.2 Charge Transfer at a Semiconductor/Liquid Junction 229
7.5 The Current-Voltage Behaviours of a Semiconductor/Liquid Junction 231
7.5.1 The Current-Voltage Characteristics of a Semiconductor/Liquid Junction in Dark 231
7.5.2 The Current-Voltage Characteristics of a Semiconductor/Liquid Junction under Illumination 233
7.6 Energy Conversion Efficiency 234
7.7 Summary 235
References 236
8 Photoelectrocatalytic Solar Water Splitting 241
Deyu Liu and Yongbo Kuang
8.1 Introduction 241
8.2 Basic Concepts of Nonbiased PEC System 242
8.2.1 Thermodynamics of PEC System 242
8.2.2 Photoelectrodes and Photoelectrochemical Cells 244
8.2.3 Unbiased PEC Solar Water Splitting Cells 245
8.2.4 Selection of Semiconducting Materials 246
8.3 Design of Photoelectrodes from System-Wide View 250
8.3.1 From Semiconductor Materials to Photoelectrodes 250
8.3.2 Parameters of the Photoelectrodes 252
8.3.3 Functionalization Layers and Cocatalysts 255
8.3.4 Testing and Operation Conditions 258
8.4 Design of Integrated PEC Systems 261
8.5 Techno-Economic Assessment 264
8.6 Summary and Overlook 268
References 271
9 Photoelectrochemical Reduction of CO2 275
Yuchen Qin and Haoyi Wu
9.1 Introduction 275
9.2 Fundamental Principles of PEC CO2 Reduction 276
9.2.1 Mechanism 276
9.2.2 Reaction Conditions 277
9.2.2.1 pH Value 277
9.2.2.2 Electrolyte Type 277
9.2.2.3 Reaction Temperature and Pressure 278
9.2.3 Evaluation Parameters for PEC CO2 Reduction 278
9.2.3.1 Product Evolution Rate and Catalytic Current Density 278
9.2.3.2 Faradaic Efficiency 278
9.2.3.3 Turnover Number and Turnover Frequency 278
9.2.3.4 Quantum Yield 279
9.3 Strengthen Strategies for PEC CO2 Reduction 279
9.3.1 Advanced Design for Photoelectrode 279
9.3.1.1 Photocathodes and Dark Anodes 279
9.3.1.2 Photoanodes and Dark Cathodes 285
9.3.1.3 Photoanodes and Photocathodes 286
9.3.1.4 PEC-Photovoltaic Cell Tandem and Wireless Monolithic Devices 286
9.3.2 PEC Reactor Configuration 287
9.3.2.1 Light Source 288
9.3.2.2 Heat Transfer 289
9.3.2.3 Utilization of CO2 289
9.3.2.4 Classification of Reactors 289
9.4 Summary and Perspectives 289
References 292
10 Photoelectrochemical Oxygen Evolution 301
Hoi Ying Chung, Hao Wu, Xuelian Wu, Chenliang Su, and Yun Hau Ng
10.1 Introduction of Photoelectrochemical Oxygen Evolution 301
10.2 Working Principles of Photoelectrochemical Oxygen Evolution 302
10.3 Promising Visible Light Active Photoanode for PEC Oxygen Evolution 305
10.3.1 Tungsten Oxide (WO3) Photoanode 305
10.3.2 Hematite (α-Fe2O3) Photoanode 308
10.3.3 Bismuth-Based Ternary Oxide Photoanode 311
10.3.3.1 Bismuth vanadate (BiVO4) 312
10.3.3.2 Bismuth Tungstate (Bi2WO6) 319
10.3.3.3 Bismuth Molybdate (Bi2MoO6) 322
10.3.4 Tantalum Oxynitride (TaON) and Tantalum Nitride (Ta3N5) 324
10.4 Summary and Outlook 328
References 329
11 Photoelectrochemical Nitrogen Reduction Reaction 339
Gnanaprakasam Janani, Subramani Surendran, Hyeonuk Choi, and Uk Sim
11.1 Introduction 339
11.2 Nitrogen Reduction Reaction 341
11.3 Photoelectrochemistry for Provision of Sustainable Energy Sources 342
11.4 Fundamentals of Photoelectrochemical Nitrogen Reduction Reaction (PEC NRR) 344
11.5 Hitches in NRR 347
11.5.1 Semiconductor Considerations 347
11.5.2 H2 Evolution Reaction and Selectivity 348
11.6 Mechanisms 350
11.7 Contribution of Catalysts in PEC NRR 352
11.7.1 Semiconductors 352
11.7.2 Plasmon-Induced Ammonia Synthesis 360
11.7.3 Black Phosphorus-based Catalysts 366
11.7.4 Role of Diamond 367
11.8 Beyond Conventional Catalysts 369
11.8.1 Electrolytes 370
11.8.2 Diffusion of N2 Gas 370
11.8.3 Prototypes 370
11.8.4 N2 Adsorption and Activation on the Catalyst Surface 371
11.9 Methods to Measure Ammonia 373
11.9.1 Colorimetric Method 373
11.9.2 Ion Chromatography Method 374
11.9.3 Ion-Selective Electrode Method 374
11.9.4 Fluorometric Method 375
11.9.5 Conductivity Method 375
11.9.6 Titrimetric Method 376
11.9.7 In situ Fourier Transform Infrared spectroscopy 376
11.9.8 Nuclear Magnetic Resonance 376
11.10 Formulas 377
11.11 From the Holy Grail to Practical Systems 377
11.12 Conclusion 378
References 378
12 Photocatalytic Oxygen Reduction 389
Hai-Ying Jiang and Xianguang Meng
12.1 Formation of ROS 389
12.2 Detection of ROS 393
12.2.1 Detection of 1O2 393
12.2.2 Detection of O-⋅2 394
12.3 Detection of H2O2 397
12.3.1 DPD-POD Method 397
12.3.2 DMP Method 398
12.4 Detection of ⋅OH 398
12.5 Applications of Photocatalytic Oxygen Reduction 402
12.5.1 Synthetic Applications 403
12.5.2 Environmental Applications 404
12.5.3 Photocatalytic H2O2 Synthesis 405
References 409
13 Photocatalytic Hydrogen Production 415
Zhen Li, Mengqing Hu, Yanqi Xu, Di Zhao, Shuaiyu Jiang, Kaicai Fan, Meng Zu, Mohammad Al-Mamun, Huajie Yin, Shan Chen, Yuhai Dou, Lei Zhang, Yu L. Zhong, Yun Wang, Shanqing Zhang, Porun Liu, and Huijun Zhao
13.1 Introduction 415
13.2 Fundamental of Heterogeneous Photocatalysis 416
13.2.1 History of Photocatalysis Hydrogen Evolution and Current Status 416
13.2.2 Thermodynamics of Photocatalytic Processes for Hydrogen Evolution 420
13.2.3 Evaluation Criteria of Efficiency for Photocatalytic Hydrogen Evolution 422
13.2.4 Key Parameters of Photocatalytic Processes 423
13.3 Enhancement for One-Step Photoexcitation for PCHER 425
13.3.1 Band Structure 425
13.3.2 Exposed Facet Engineering 427
13.3.3 Control on Microstructure and Surface Area 429
13.3.4 Doping /Vacancies/Defects 431
13.3.4.1 Metal Doping 432
13.3.4.2 Non-Metal Doping 433
13.3.4.3 Vacancies/Defects 435
13.3.5 Hole Scavenger 436
13.3.5.1 Inorganic Salts and Organic Salts 436
13.3.5.2 Organic Compounds 437
13.3.5.3 Lignocellulosic Biomass 439
13.4 Enhancement for Two-step Photoexcitation for PCHER 440
13.4.1 Surface Sensitization 442
13.4.1.1 Semiconductors Act as the Light Absorber 442
13.4.1.2 Semiconductors Act as the Reaction Sites 445
13.4.1.3 Semiconductors Act as Both Light Absorber and the Reaction Site 448
13.4.2 Type I, II, III Heterojunctions 449
13.4.3 Z-Scheme Heterojunctions 450
13.4.3.1 Z-Scheme with a Shuttle Redox Mediator 451
13.4.3.2 Z-Scheme with a Solid Mediator 453
13.4.3.3 Direct Z-Scheme 453
13.5 Enhancement with Other Operation Parameters 456
13.5.1 Backward/Side Reactions 457
13.5.2 Improved Mass Transfer 457
13.5.3 Corrosion Resistance 458
13.5.4 Temperature 459
13.5.5 Light Intensity 459
13.5.6 Solution pH 460
13.5.7 Design of Reactor 460
13.6 Summary and Perspectives 462
References 464
14 Photocatalytic Oxygen Evolution 485
Wenzhang Li and Keke Wang
14.1 Introduction 485
14.2 Basic of Photocatalytic Water Splitting 486
14.2.1 History of Photocatalytic Water Splitting 486
14.2.2 Fundamentals of Photocatalytic Water Splitting 489
14.2.3 Half-Reactions Using Sacrificial Electron Donors and Acceptors 491
14.3 Semiconductor Photocatalysts 492
14.3.1 Brief History of Semiconductor Photocatalysts 492
14.3.2 Advancements in Photocatalyst Materials 493
14.3.2.1 Doping 493
14.3.2.2 Heterostructures 499
14.3.2.3 Morphology Control 507
14.3.2.4 Cocatalyst Loading 510
14.4 Conclusion Remarks and Future Directions 513
References 514
15 Photocatalytic Overall Water Splitting 521
Ning Zhang
15.1 Background 521
15.2 Evaluation of Overall Water Splitting 524
15.2.1 Stoichiometric Evolved Gaseous H2 and O2 524
15.2.2 Calculation of Turnover Number 525
15.2.3 Calculation of Quantum Yield 526
15.3 Photocatalysts 526
15.3.1 Single Semiconductor 526
15.3.2 Z-Scheme System 530
15.3.3 Heterojunctions 532
15.3.4 Polymers 535
15.4 Conclusions and Prospects 538
References 538
16 Photocatalytic CO2 Reduction 541
Deli Jiang, Qi Song, Yuyan Xu, and Di Li
16.1 Introduction 541
16.2 Principle and Mechanism of CO2 Reduction 542
16.2.1 Thermodynamics of CO2 Reduction 542
16.2.2 Kinetics of CO2 Reduction 543
16.2.3 CO2 Adsorption Configurations 544
16.3 Strategies to Improve the Photocatalytic CO2 Reduction Activities 544
16.3.1 Defect Engineering 545
16.3.1.1 Anions Vacancies 545
16.3.1.2 Cations Vacancies 547
16.3.2 Loading of Metal Co-catalyst 550
16.3.2.1 Loading of Pt Nanoparticles 550
16.3.2.2 Loading of Pd Nanoparticles 551
16.3.2.3 Loading of Ag Nanoparticles 553
16.3.2.4 Loading of Alloys Nanoparticles 555
16.3.3 Construction of Heterojunctions 557
16.3.3.1 II-Typical Heterojunctions 558
16.3.3.2 Z-Scheme Heterojunction 559
16.4 Conclusions 562
Acknowledgment 562
References 562
Index 569
