Chemical Energy Storage (eBook)

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Robert Schlögl, Fritz-Haber-Institut derMax-Planck-Gesellschaft, Berlin, Germany.

Author Index 15
1.1 The Solar Refinery 21
1.1.1 Introduction 21
1.1.2 The Role of Chemistry in the Energy Challenge 25
1.1.3 Chemical Reactions and Catalysis 27
1.1.4 The Design of Catalysts and Processes 36
1.1.5 The Biological Origin of Our Present Energy System 37
1.1.6 Chemical Energy Storage: One Long-Term Solution 40
1.1.7 References 50
1.2 Energy Storage Strategies 55
1.2.1 Introduction 55
1.2.2 General Considerations 55
1.2.3 Heat (Cold) Storage 57
1.2.4 Grid-Scale Storage of Electrical Energy 59
1.2.4.1 Storage on the Transmission Grid Scale 60
1.2.4.2 Storage on Distribution and Medium-Voltage Grid Scale 63
1.2.5 Energy Storage for Mobile Applications 64
1.2.5.1 Chemical Compounds 65
1.2.5.2 Traction Batteries 66
1.2.6 Systems Considerations 67
1.3 Energy and Society: A Practical Guide 69
1.3.1 Notes 77
1.3.2 References 77
2.1 Biofuels Derived from Renewable Feedstocks 79
2.1.1 Introduction 79
2.1.2 Sources of Biomass 79
2.1.3 Lignocellulose as Feedstock 82
2.1.4 Bioethanol as Sustainable Biofuel 83
2.1.5 Biodiesel as Potential Biofuel 86
2.1.6 Production of Biofuel via Chemical Transformations of Lignocellulose 88
2.1.7 Controlled Transformations of Carbohydrates into Hydrocarbon Fuels 92
2.1.8 Controlled Transformations of Carbohydrates into Novel Biofuels 96
2.1.8.1 Transformations Based on LA 97
2.1.8.2 Biofuel Compounds Based on 5-HMF 99
2.1.9 Controlled Transformations of Lignin into Potential Fuel Compounds 101
2.1.10 Summary 102
2.1.11 Acknowledgment 102
2.1.12 References 102
2.2 Biomass Conversion to Chemicals 107
2.2.1 Introduction 107
2.2.2 Classification of Biomass 108
2.2.2.1 Lignocellulose 109
2.2.2.2 Lipids 114
2.2.2.3 Proteins 118
2.2.3 Selected Key Chemicals 118
2.2.3.1 Cellulose 118
2.2.3.2 Glycerol 119
2.2.4 Technologies and Requirements for Chemical Production from Biomass 123
2.2.5 Economic Considerations 124
2.2.6 Outlook 125
2.2.7 References 125
2.3 Thermal Conversion of Biomass 129
2.3.1 Torrefaction 132
2.3.2 Pyrolysis 132
2.3.2.1 Introduction 132
2.3.2.2 Pyrolysis Reactors 133
2.3.2.3 Biomass 134
2.3.2.4 Composition of Bio-Oil 134
2.3.2.5 Utilization of Bio-Oil 135
2.3.2.6 Upgrading of Bio-Oil 135
2.3.3 Gasification 136
2.3.3.1 Introduction 136
2.3.3.2 Gasification Reactors 137
2.3.3.3 Energy in Gasification 138
2.3.4 Combustion 138
2.3.4.1 Introduction 138
2.3.4.2 Energy in Combustion 139
2.3.4.3 Co-combustion 139
2.3.5 Summary 140
2.3.6 References 141
2.4 Biomass to Mineralized Carbon: Energy Generation and/or Carbon Sequestration 145
2.4.1 Introduction 145
2.4.2 HTC 146
2.4.2.1 HTC of Biomass Waste for Environmentally Friendly Carbon Sequestration 146
2.4.2.2 HTC for “Carbon-Negative Materials” 147
2.4.3 Mineralized Biomass as Energy Carrier 149
2.4.3.1 “Biocoal” and Its Comparison to Other Biofuels, Biogas and Bioethanol 149
2.4.3.2 Carbon Fuel Cells 152
2.4.4 Discussion and Conclusion 153
2.4.5 References 153
3.1 Electrochemical Concepts: A Practical Guide 155
3.1.1 Introduction 155
3.1.2 Electrodes in Electrolytes 157
3.1.3 Energetics of Electrode Reactions 158
3.1.4 The Electrochemical Cell 160
3.1.4.1 The Concept 160
3.1.4.2 Chemical and Electric Energy 162
3.1.4.3 The Maximum Electric Energy Produced and the Equilibrium Cell Voltage 164
3.1.5 Concentration Dependence of E: The Nernst Equation 165
3.1.5.1 The Nernst Equation 165
3.1.5.2 Concentration Cells 167
3.1.6 The Temperature Dependence of the Equilibrium Cell Voltage, E 168
3.1.7 Conclusion 168
3.1.8 Acknowledgment 169
3.1.9 References 170
3.2 Water-Splitting Conceptual Approach 171
3.2.1 Introduction 171
3.2.2 Fundamentals 171
3.2.3 Standard (Reversible) Hydrogen Electrode 172
3.2.4 The Cathode Half-Cell Reaction 173
3.2.5 The Anode Half-Cell Reaction 174
3.2.5.1 Free Energy Diagram 175
3.2.5.2 Tafel Equation and .GOER 176
3.2.5.3 Scaling Relations 178
3.2.5.4 Universal Scaling and Trends in Activity 179
3.2.6 Conclusion 181
3.2.7 References 181
3.3 Fuel Cells 183
3.3.1 What Is a Fuel Cell? 184
3.3.2 Components of a Fuel Cell 185
3.3.3 Performance Characteristics of a Fuel Cell 190
3.3.4 The Electrocatalysis of Oxygen Reduction at Fuel Cell Cathodes 193
3.3.4.1 Understanding the Electrode Potential Dependence of the ORR 193
3.3.4.2 Understanding and Predicting Trends in ORR Activity on Transition-Metal Catalysts 194
3.3.4.3 Nanostructured Pt Core-Shell Electrocatalysts for the ORR 197
3.3.4.4 Noble-Metal-Free ORR PEMFC Electrocatalysts 202
3.3.5 Conclusions 202
3.3.6 Acknowledgments 203
3.3.7 References 203
3.4 Molecular Concepts of Water Splitting: Nature’s Approach 205
3.4.1 Introduction 205
3.4.2 Water Oxidation 207
3.4.2.1 PSII 207
3.4.2.2 Geometric Structure of the WOC 210
3.4.2.3 Electronic Structure of the WOC 212
3.4.2.4 Function of the WOC 214
3.4.2.5 Suggested Mechanisms of O-O Bond Formation 215
3.4.2.6 Summary: Principles of Photosynthetic Water Splitting 217
3.4.2.7 Current Water-Splitting Catalysts 218
3.4.3 Hydrogen Production and Conversion 219
3.4.3.1 Classification of Hydrogenases 220
3.4.3.2 Structure of [NiFe] and [FeFe] Hydrogenases 220
3.4.3.3 Intermediate States and Reaction Mechanisms 223
3.4.3.4 Oxygen Sensitivity and Tolerance 229
3.4.3.5 Design Principles of Hydrogenases 230
3.4.3.6 Molecular Catalysts for H2 Conversion and Production 231
3.4.4 Conclusions 233
3.4.5 Acknowledgments 234
3.4.6 Notes 234
3.4.7 References 235
3.5 Batteries: Concepts and Systems 245
3.5.1 Introduction 245
3.5.2 Secondary Battery Systems 248
3.5.3 Lithium Batteries 252
3.5.4 Thermodynamics of Electrochemical Energy Storage 256
3.5.5 Kinetics of Energy Storage 259
3.5.6 Materials Optimization: Adjusting Screws 260
3.5.7 Outlook 264
3.5.8 Acknowledgments 264
3.5.9 Note 265
3.5.10 References 265
4.1 Chemical Kinetics: A Practical Guide 269
4.1.1 Theory 269
4.1.1.1 Introduction 269
4.1.1.2 Course of a Catalytic Reaction 269
4.1.1.3 Reaction Kinetics 271
4.1.2 Practical Aspects 278
4.1.2.1 Laboratory Reactors 278
4.1.2.2 Preliminary Tests 278
4.1.2.3 Comparative Studies 279
4.1.2.4 Development of Kinetic Models 280
4.1.3 Examples 284
4.1.3.1 Oxidative Coupling of Methane 284
4.1.3.2 Decomposition of Ammonia 287
4.1.3.3 Slurry Reaction 290
4.1.4 Notes 293
4.1.5 Acknowledgment 294
4.1.6 Abbreviations 294
4.1.7 References 295
4.2 Synthesis of Solid Catalysts 297
4.2.1 Macroscopic Catalyst Bodies 300
4.2.2 The Active Phase 305
4.2.3 Dispersed Surface Species 316
4.2.4 Final Remarks 320
4.2.5 Acknowledgments 321
4.2.6 References 321
4.3 In situ Analysis of Heterogeneous Catalysts in Chemical Energy Conversion 331
4.3.1 Setting the Scene for Catalyst Characterization in Energy-Related Catalysis and Energy Storage 331
4.3.2 The Bench of Complementary Characterization Methods 332
4.3.3 Importance of In Situ Studies 334
4.3.4 In Situ Cell Design: A Challenge between Engineering and Spectroscopy for Dynamic Experiments and Structure Performance Relationships 336
4.3.5 Case Studies in Gas Phase, Liquid Phase, High Pressure, and Other Demanding Reaction Conditions 338
4.3.6 Watching Ensembles and Reactors at Work: Spatially Resolved Studies 341
4.3.7 Conclusions and Outlook 343
4.3.8 Acknowledgment 344
4.3.9 References 344
4.4 Model Systems in Catalysis for Energy Economy 349
4.4.1 Introduction 349
4.4.2 First Case Study: Controlling Nanoparticle Shapes on Nondoped and Doped Oxide Supports 351
4.4.3 Second Case Study: Preparation of Oxide-Supported Palladium Model Catalysts by Pd Deposition from Solution 356
4.4.4 Third Case Study: Strong Metal/Support Interaction Effects 360
4.4.5 Fourth Case Study: Photochemistry at Nanoparticles 364
4.4.6 Synopsis 368
4.4.7 References 368
4.5 Challenges in Molecular Energy Research 373
4.5.1 Introduction 373
4.5.2 Modern Spectroscopy and Quantum Chemistry as a Means to Decipher Reaction Mechanisms 375
4.5.3 Fundamental Chemistry of Energy Conversion 377
4.5.3.1 Hydrogen Production 377
4.5.3.2 Water Oxidation 380
4.5.3.3 Oxygen Activation 384
4.5.3.4 Methane Oxidation 388
4.5.3.5 Conversion of Dinitrogen to Ammonia 390
4.5.4 Summary and Outlook 392
4.5.5 Acknowledgments 393
4.5.6 References 393
5.1 Photoelectrochemical CO2 Activation toward Artificial Leaves 399
5.1.1 Introduction 399
5.1.2 Artificial Leaves and PEC CO2 Activation 400
5.1.3 Fundamentals of Water and CO2 Electrolysis 402
5.1.4 Designing the Electrocatalytic Cathode for CO2 Reduction 408
5.1.5 Designing the Photoanode 411
5.1.6 PEC Cells for CO2 Conversion 415
5.1.7 Conclusions 417
5.1.8 References 418
5.2 Thermochemical CO2 Activation 421
5.2.1 Introduction 421
5.2.2 General Kinetic and Thermodynamic Considerations 422
5.2.3 Solarthermal Cycles 423
5.2.3.1 General Principles 423
5.2.3.2 Examples 428
5.2.4 Dry Reforming of Methane 431
5.2.5 Summary 431
5.2.6 References 431
5.3 Methanol Chemistry 433
5.3.1 Why Methanol? 433
5.3.2 Introduction to Methanol Synthesis and Steam Reforming 435
5.3.3 Today’s Industrial Methanol Synthesis 437
5.3.4 The Reaction Mechanism of Methanol Synthesis 439
5.3.5 Methanol Synthesis from CO2: Thermodynamic and Kinetic Considerations 442
5.3.6 Cu/ZnO-Based Methanol Synthesis Catalysts 446
5.3.7 Methanol Steam Reforming (MSR)2 450
5.3.8 Challenges and Perspectives in Catalyst and Process Development for Energy-Related Application of Methanol 453
5.3.9 Notes 455
5.3.10 References 455
5.4 Synthesis Gas to Hydrogen, Methanol, and Synthetic Fuels 463
5.4.1 Introduction 463
5.4.2 Production of Synthesis Gas 463
5.4.3 Applications of Synthesis Gas: H2 and Methanol 465
5.4.3.1 Syngas to Hydrogen: The WGS Reaction 465
5.4.3.2 Syngas to Methanol 466
5.4.4 Syngas to Synthetic Fuels: The Fischer-Tropsch Synthesis 466
5.4.4.1 Chemistry and Catalysts 467
5.4.5 References 475
Index 479