Electrocatalysis in Balancing the Natural Carbon Cycle

Explore the potential of electrocatalysis to balance an off-kilter natural carbon cycle

In Electrocatalysis in Balancing the Natural Carbon Cycle, accomplished researcher and author, Yaobing Wang, delivers a focused examination of why and how to solve the unbalance of the natural carbon cycle with electrocatalysis. The book introduces the natural carbon cycle and analyzes current bottlenecks being caused by human activities. It then examines fundamental topics, including CO₂ reduction, water splitting, and small molecule (alcohols and acid) oxidation to prove the feasibility and advantages of using electrocatalysis to tune the unbalanced carbon cycle.

You?ll realize modern aspects of electrocatalysis through the operando diagnostic and predictable mechanistic investigations. Further, you will be able to evaluate and manage the efficiency of the electrocatalytic reactions. The distinguished author presents a holistic view of solving an unbalanced natural carbon cycle with electrocatalysis.

Readers will also benefit from the inclusion of:

• A thorough introduction to the natural carbon cycle and the anthropogenic carbon cycle, including inorganic carbon to organic carbon and vice versa
• An exploration of electrochemical catalysis processes, including water splitting and the electrochemistry CO₂ reduction reaction (ECO₂RR)
• A practical discussion of water and fuel basic redox parameters, including electrocatalytic materials and their performance evaluation in different electrocatalytic cells
• A perspective of the operando approaches and computational fundamentals and advances of different electrocatalytic redox reactions

Perfect for electrochemists, catalytic chemists, environmental and physical chemists, and inorganic chemists, Electrocatalysis in Balancing the Natural Carbon Cycle will also earn a place in the libraries of solid state and theoretical chemists seeking a one-stop reference for all aspects of electrocatalysis in carbon cycle-related reactions.

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 (j_kand 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

Yaobing Wang is Professor at the Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences. He received his doctorate from the Institute of Chemistry, Chinese Academy of Sciences in 2008 and his research focuses on the design and synthesis of novel electrocatalysts and their applications.