Electrocatalysis in Balancing the Natural Carbon Cycle

Preface xv Acknowledgments xix Part I Introduction 1 1 Introduction 3 References 5 Part II Natural Carbon Cycle 7 2 Natural Carbon Cycle and Anthropogenic Carbon Cycle 9 2.1 Definition and General Process 9 2.2 From Inorganic Carbon to Organic Carbon 10 2.3 From Organic Carbon to Inorganic Carbon 11 2.4 Anthropogenic Carbon Cycle 11 2.4.1 Anthropogenic Carbon Emissions 12 2.4.2 Capture and Recycle of CO2 from the Atmosphere 13 2.4.3 Fixation and Conversion of CO2 14 2.4.3.1 Photochemical Reduction 14 2.4.3.2 Electrochemical Reduction 15 2.4.3.3 Chemical/Thermo Reforming 16 2.4.3.4 Physical Fixation 16 2.4.3.5 Anthropogenic Carbon Conversion and Emissions Via Electrochemistry 17 References 18 Part III Electrochemical Catalysis Process 21 3 Electrochemical Catalysis Processes 23 3.1 Water Splitting 23 3.1.1 Reaction Mechanism 23 3.1.1.1 Mechanism of OER 23 3.1.1.2 Mechanism of ORR 24 3.1.1.3 Mechanism of HER 26 3.1.2 General Parameters to Evaluate Water Splitting 27 3.1.2.1 Tafel Slope 27 3.1.2.2 TOF 27 3.1.2.3 Onset/Overpotential 28 3.1.2.4 Stability 28 3.1.2.5 Electrolyte 28 3.2 Electrochemistry CO2 Reduction Reaction (ECDRR) 29 3.2.1 Possible Reaction Pathways of ECDRR 29 3.2.1.1 Formation of HCOO− or HCOOH 29 3.2.1.2 Formation of CO 30 3.2.1.3 Formation of C1 Products 30 3.2.1.4 Formation of C2 Products 31 3.2.1.5 Formation of CH3COOH and CH3COO− 33 3.2.1.6 Formation of n-Propanol (C3 Product) 33 3.2.2 General Parameters to Evaluate ECDRR 34 3.2.2.1 Onset Potential 34 3.2.2.2 Faradaic Efficiency 34 3.2.2.3 Partial Current Density 34 3.2.2.4 Environmental Impact and Cost 35 3.2.2.5 Electrolytes 35 3.2.2.6 Electrochemical Cells 36 3.3 Small Organic Molecules Oxidation 36 3.3.1 The Mechanism of Electrochemistry HCOOH Oxidation 36 3.3.2 The Mechanism of Electro-oxidation of Alcohol 37 References 40 Part IV Water Splitting and Devices 43 4 Water Splitting Basic Parameter/Others 45 4.1 Composition and Exact Reactions in Different pH Solution 45 4.2 Evaluation of the Catalytic Activity 47 4.2.1 Overpotential 47 4.2.2 Tafel Slope 48 4.2.3 Stability 49 4.2.4 Faradaic Efficiency 49 4.2.5 Turnover Frequency 50 References 50 5 H2O Oxidation 53 5.1 Regular H2O Oxidation 53 5.1.1 Noble Metal Catalysts 53 5.1.2 Other Transition Metals 64 5.1.3 Other Catalysts 72 5.2 Photo-Assisted H2O Oxidation 76 5.2.1 Metal Compound-Based Catalysts 76 5.2.2 Metal–Metal Heterostructure Catalysts 80 5.2.3 Metal–Nonmetal Heterostructure Catalysts 86 References 88 6 H2O Reduction and Water Splitting Electrocatalytic Cell 91 6.1 Noble-Metal-Based HER Catalysts 91 6.2 Non-Noble Metal Catalysts 93 6.3 Water Splitting Electrocatalytic Cell 96 References 99 Part V H2 Oxidation/O2 Reduction and Device 101 7 Introduction 103 7.1 Electrocatalytic Reaction Parameters 104 7.1.1 Electrochemically Active Surface Area (ECSA) 104 7.1.1.1 Test Methods 104 7.1.2 Determination Based on the Surface Redox Reaction 104 7.1.3 Determination by Electric Double-Layer Capacitance Method 105 7.1.4 Kinetic and Exchange Current Density (jk and j0) 105 7.1.4.1 Definition 105 7.1.4.2 Calculation 106 7.1.5 Overpotential HUPD 106 7.1.6 Tafel Slope 108 7.1.7 Halfwave Potentials 108 References 108 8 Hydrogen Oxidation Reaction (HOR) 111 8.1 Mechanism for HOR 111 8.1.1 Hydrogen Bonding Energy (HBE) 111 8.1.2 Underpotential Deposition (UPD) of Hydrogen 112 8.2 Catalysts for HOR 112 8.2.1 Pt-based Materials 112 8.2.2 Pd-Based Materials 120 8.2.3 Ir-Based Materials 121 8.2.4 Rh-Based Materials 121 8.2.5 Ru-Based Materials 121 8.2.6 Non-noble Metal Materials 122 References 130 9 Oxygen Reduction Reaction (ORR) 133 9.1 Mechanism for ORR 133 9.1.1 Battery System and Damaged Electrodes 133 9.1.2 Intermediate Species 134 9.2 Catalysts in ORR 134 9.2.1 Noble Metal Materials 134 9.2.1.1 Platinum/Carbon Catalyst 138 9.2.1.2 Pd and Pt 145 9.2.2 Transition Metal Catalysts 145 9.2.3 Metal-Free Catalysts 149 9.3 Hydrogen Peroxide Synthesis 154 9.3.1 Catalysts Advances 154 9.3.1.1 Pure Metals 154 9.3.1.2 Metal Alloys 156 9.3.1.3 Carbon Materials 157 9.3.1.4 Electrodes and Reaction Cells 158 References 161 10 Fuel Cell and Metal-Air Battery 167 10.1 H2 Fuel Cell 167 10.2 Metal-Air Battery 170 10.2.1 Metal-Air Battery Structure 171 References 181 Part VI Small Organic Molecules Oxidation and Device 183 11 Introduction 185 11.1 Primary Measurement Methods and Parameters 186 11.1.1 Primary Measurement Methods 186 11.1.2 Primary Parameter 193 References 197 12 C1 Molecule Oxidation 199 12.1 Methane Oxidation 199 12.1.1 Reaction Mechanism 199 12.1.1.1 Solid–Liquid–Gas Reaction System 199 12.1.2 Acidic Media 199 12.1.3 Alkaline or Neutral Media 201 12.2 Methanol Oxidation 203 12.2.1 Reaction Thermodynamics and Mechanism 203 12.2.2 Catalyst Advances 204 12.2.2.1 Pd-Based Catalysts 204 12.2.2.2 Pt-Based Catalysts 208 12.2.2.3 Platinum-Based Nanowires 208 12.2.2.4 Platinum-Based Nanotubes 210 12.2.2.5 Platinum-Based Nanoflowers 212 12.2.2.6 Platinum-Based Nanorods 214 12.2.2.7 Platinum-Based Nanocubes 215 12.2.3 Pt–Ru System 217 12.2.4 Pt–Sn Catalysts 218 12.3 Formic Acid Oxidation 219 12.3.1 Reaction Mechanism 219 12.3.2 Catalyst Advances 220 12.3.2.1 Pd-Based Catalysts 220 12.3.2.2 Pt-Based Catalysts 223 References 226 13 C2+ Molecule Oxidation 235 13.1 Ethanol Oxidation 235 13.1.1 Reaction Mechanism 235 13.1.2 Catalyst Advances 235 13.1.2.1 Pd-Based Catalysts 235 13.1.2.2 Pt-Based Catalysts 239 13.1.2.3 Pt–Sn System 243 13.2 Glucose Oxidase 250 13.3 Ethylene Glycol Oxidation 251 13.4 Glycerol Oxidation 251 References 254 14 Fuel Cell Devices 257 14.1 Introduction 257 14.2 Types of Direct Liquid Fuel Cells 258 14.2.1 Acid and Alkaline Fuel Cells 258 14.2.2 Direct Methanol Fuel Cells (DMFCs) 260 14.2.3 Direct Ethanol Fuel Cells (DEFCs) 261 14.2.4 Direct Ethylene Glycol Fuel Cells (DEGFCs) 261 14.2.5 Direct Glycerol Fuel Cells (DGFCs) 262 14.2.6 Direct Formic Acid Fuel Cells (DFAFCs) 262 14.2.7 Direct Dimethyl Ether Fuel Cells (DDEFCs) 263 14.2.8 Other DLFCs 263 14.2.9 Challenges of DLFCs 264 14.2.10 Fuel Conversion and Cathode Flooding 264 14.2.11 Chemical Safety and By-product Production 265 14.2.12 Unproven Long-term Durability 265 References 267 Part VII CO2 Reduction and Device 271 15 Introduction 273 15.1 Basic Parameters of the CO2 Reduction Reaction 276 15.1.1 The Fundamental Parameters to Evaluate the Catalytic Activity 276 15.1.1.1 Overpotential (𝜂) 276 15.1.1.2 Faradaic Efficiency (FE) 276 15.1.1.3 Current Density ( j) 277 15.1.1.4 Energy Efficiency (EE) 277 15.1.1.5 Tafel Slope 278 15.1.2 Factors Affecting ECDRR 278 15.1.2.1 Solvent/Electrolyte 278 15.1.2.2 pH 280 15.1.2.3 Cations and Anions 281 15.1.2.4 Concentration 282 15.1.2.5 Temperature and Pressure Effect 282 15.1.3 Electrode 283 15.1.3.1 Loading Method 283 15.1.3.2 Preparation 284 15.1.3.3 Experimental Process and Analysis Methods 284 References 285 16 Electrocatalysts-1 289 16.1 Heterogeneous Electrochemical CO2 Reduction Reaction 289 16.2 Thermodynamic and Kinetic Parameters of Heterogeneous CO2 Reduction in Liquid Phase 289 16.2.1 Bulk Metals 293 16.2.2 Nanoscale Metal and Oxidant Metal Catalysts 294 16.2.2.1 Gold (Au) 295 16.2.2.2 Silver (Ag) 296 16.2.2.3 Palladium (Pd) 297 16.2.2.4 Zinc (Zn) 298 16.2.2.5 Copper (Cu) 299 16.2.3 Bimetallic/Alloy 301 References 306 17 Electrocatalysts-2 309 17.1 Single-Atom Metal-Doped Carbon Catalysts (SACs) 309 17.1.1 Nickel (Ni)-SACs 309 17.1.2 Cobalt (Co)-SACs 311 17.1.3 Iron (Fe)-SACs 311 17.1.4 Zinc (Zn)-SACs 314 17.1.5 Copper (Cu)-SACs 314 17.1.6 Other 316 17.2 Metal Nanoparticles-Doped Carbon Catalysts 317 17.3 Porous Organic Material 320 17.3.1 Metal Organic Frameworks (MOFs) 320 17.3.2 Covalent Organic Frameworks (COFs) 321 17.3.3 Metal-Free Catalyst 322 17.4 Metal-Free Carbon-Based Catalyst 322 17.4.1 Other Metal-Free Catalyst 324 17.5 Electrochemical CO Reduction Reaction 324 17.5.1 The Importance of CO Reduction Study 324 17.5.2 Advances in CO Reduction 326 References 327 18 Devices 331 18.1 H-Cell 331 18.2 Flow Cell 333 18.3 Requirements and Challenges for Next-Generation CO2 Reduction Cell 338 18.3.1 Wide Range of Electrocatalysts 338 18.3.2 Fundamental Factor Influencing the Catalytic Activity for ECDRR 339 18.3.3 Device Engineering 340 References 342 Part VIII Computations-Guided Electrocatalysis 345 19 Insights into the Catalytic Process 347 19.1 Electric Double Layer 347 19.2 Kinetics and Thermodynamics 349 19.3 Electrode Potential Effects 350 References 352 20 Computational Electrocatalysis 355 20.1 Computational Screening Toward Calculation Theories 356 20.2 Reactivity Descriptors 358 20.2.1 d-band Theory Motivates Electronic Descriptor 359 20.2.2 Coordination Numbers Motives Structure Descriptor 361 20.3 Scaling Relationships: Applications of Descriptors 361 20.4 The Activity Principles and the Volcano Curve 363 20.5 DFT Modeling 366 20.5.1 CHE Model 367 20.5.2 Solvation Models 368 20.5.3 Kinetic Modeling 371 References 374 21 Theory-Guided Rational Design 377 21.1 Descriptors-Guided Screening 377 21.2 Scaling Relationship-Guided Trends 380 21.2.1 Reactivity Trends of ECR 380 21.2.2 Reactivity Trends of O-included Reactions 382 21.2.3 Reactivity Trends of H-included Reactions 385 21.3 DOS-Guided Models and Active Sites 386 References 388 22 DFT Applications in Selected Electrocatalytic Systems 391 22.1 Unveiling the Electrocatalytic Mechanism 391 22.1.1 ECR Reaction 393 22.1.2 OER Reaction 394 22.1.3 ORR Reaction 396 22.1.4 HER Reaction 397 22.1.5 HOR Reaction 398 22.1.6 CO Oxidation Reaction 400 22.1.7 FAOR Reaction 402 22.1.8 MOR Reaction 402 22.1.9 EOR Reaction 404 22.2 Understanding the Electrocatalytic Environment 406 22.2.1 Solvation Effects 406 22.2.2 pH Effects 409 22.3 Analyzing the Electrochemical Kinetics 410 22.4 Perspectives, Challenges, and Future Direction of DFT Computation in Electrocatalysis 413 References 414 Part IX Potential of In Situ Characterizations for Electrocatalysis 421 References 422 23 In Situ Characterization Techniques 423 23.1 Optical Characterization Techniques 423 23.1.1 Infrared Spectroscopy 423 23.1.2 Raman Spectroscopy 424 23.1.3 UV–vis Spectroscopy 426 23.2 X-Ray Characterization Techniques 427 23.2.1 X-Ray Diffraction (XRD) 429 23.2.2 X-Ray Absorption Spectroscopy (XAS) 429 23.2.3 X-Ray Photoelectron Spectroscopy (XPS) 431 23.3 Mass Spectrometric Characterization Techniques 431 23.4 Electron-Based Characterization Techniques 432 23.4.1 Transmission Electron Microscopy (TEM) 434 23.4.2 Scanning Probe Microscopy (SPM) 434 References 436 24 In Situ Characterizations in Electrocatalytic Cycle 441 24.1 Investigating the Real Active Centers 441 24.1.1 Monitoring the Electronic Structure 442 24.1.2 Monitoring the Atomic Structure 444 24.1.3 Monitoring the Catalyst Phase Transformation 446 24.2 Investigating the Reaction Mechanism 449 24.2.1 Through Adsorption/Activation Understanding 450 24.2.2 Through Intermediates In Situ Probing 451 24.2.3 Through Catalytic Product In Situ Detections 454 24.3 Evaluating the Catalyst Stability/Decay 457 24.4 Revealing the Interfacial-Related Insights 460 24.5 Conclusion 462 References 462 Part X Electrochemical Catalytic Carbon Cycle 465 References 466 25 Electrochemical CO2 Reduction to Fuels 467 References 479 26 Electrochemical Fuel Oxidation 483 References 495 27 Evaluation and Management of ECC 499 27.1 Basic Performance Index 499 27.2 CO2 Capture and Fuel Transport 500 27.3 External Management 500 27.4 General Outlook 502 References 505 Index 507