Electrocatalysis in Balancing the Natural Carbon Cycle

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.

• Preface xvAcknowledgments xixPart I Introduction 11 Introduction 3References 5Part II Natural Carbon Cycle 72 Natural Carbon Cycle and Anthropogenic Carbon Cycle 92.1 Definition and General Process 92.2 From Inorganic Carbon to Organic Carbon 102.3 From Organic Carbon to Inorganic Carbon 112.4 Anthropogenic Carbon Cycle 112.4.1 Anthropogenic Carbon Emissions 122.4.2 Capture and Recycle of CO2 from the Atmosphere 132.4.3 Fixation and Conversion of CO2 142.4.3.1 Photochemical Reduction 142.4.3.2 Electrochemical Reduction 152.4.3.3 Chemical/Thermo Reforming 162.4.3.4 Physical Fixation 162.4.3.5 Anthropogenic Carbon Conversion and Emissions ViaElectrochemistry 17References 18Part III Electrochemical Catalysis Process 213 Electrochemical Catalysis Processes 233.1 Water Splitting 233.1.1 Reaction Mechanism 233.1.1.1 Mechanism of OER 233.1.1.2 Mechanism of ORR 243.1.1.3 Mechanism of HER 263.1.2 General Parameters to Evaluate Water Splitting 273.1.2.1 Tafel Slope 273.1.2.2 TOF 273.1.2.3 Onset/Overpotential 283.1.2.4 Stability 283.1.2.5 Electrolyte 283.2 Electrochemistry CO2 Reduction Reaction (ECDRR) 293.2.1 Possible Reaction Pathways of ECDRR 293.2.1.1 Formation of HCOO− or HCOOH 293.2.1.2 Formation of CO 303.2.1.3 Formation of C1 Products 303.2.1.4 Formation of C2 Products 313.2.1.5 Formation of CH3COOH and CH3COO− 333.2.1.6 Formation of n-Propanol (C3 Product) 333.2.2 General Parameters to Evaluate ECDRR 343.2.2.1 Onset Potential 343.2.2.2 Faradaic Efficiency 343.2.2.3 Partial Current Density 343.2.2.4 Environmental Impact and Cost 353.2.2.5 Electrolytes 353.2.2.6 Electrochemical Cells 363.3 Small Organic Molecules Oxidation 363.3.1 The Mechanism of Electrochemistry HCOOH Oxidation 363.3.2 The Mechanism of Electro-oxidation of Alcohol 37References 40Part IV Water Splitting and Devices 434 Water Splitting Basic Parameter/Others 454.1 Composition and Exact Reactions in Different pH Solution 454.2 Evaluation of the Catalytic Activity 474.2.1 Overpotential 474.2.2 Tafel Slope 484.2.3 Stability 494.2.4 Faradaic Efficiency 494.2.5 Turnover Frequency 50References 505 H2O Oxidation 535.1 Regular H2O Oxidation 535.1.1 Noble Metal Catalysts 535.1.2 Other Transition Metals 645.1.3 Other Catalysts 725.2 Photo-Assisted H2O Oxidation 765.2.1 Metal Compound-Based Catalysts 765.2.2 Metal–Metal Heterostructure Catalysts 805.2.3 Metal–Nonmetal Heterostructure Catalysts 86References 886 H2O Reduction and Water Splitting Electrocatalytic Cell 916.1 Noble-Metal-Based HER Catalysts 916.2 Non-Noble Metal Catalysts 936.3 Water Splitting Electrocatalytic Cell 96References 99Part V H2 Oxidation/O2 Reduction and Device 1017 Introduction 1037.1 Electrocatalytic Reaction Parameters 1047.1.1 Electrochemically Active Surface Area (ECSA) 1047.1.1.1 Test Methods 1047.1.2 Determination Based on the Surface Redox Reaction 1047.1.3 Determination by Electric Double-Layer Capacitance Method 1057.1.4 Kinetic and Exchange Current Density (jk and j0) 1057.1.4.1 Definition 1057.1.4.2 Calculation 1067.1.5 Overpotential HUPD 1067.1.6 Tafel Slope 1087.1.7 Halfwave Potentials 108References 1088 Hydrogen Oxidation Reaction (HOR) 1118.1 Mechanism for HOR 1118.1.1 Hydrogen Bonding Energy (HBE) 1118.1.2 Underpotential Deposition (UPD) of Hydrogen 1128.2 Catalysts for HOR 1128.2.1 Pt-based Materials 1128.2.2 Pd-Based Materials 1208.2.3 Ir-Based Materials 1218.2.4 Rh-Based Materials 1218.2.5 Ru-Based Materials 1218.2.6 Non-noble Metal Materials 122References 1309 Oxygen Reduction Reaction (ORR) 1339.1 Mechanism for ORR 1339.1.1 Battery System and Damaged Electrodes 1339.1.2 Intermediate Species 1349.2 Catalysts in ORR 1349.2.1 Noble Metal Materials 1349.2.1.1 Platinum/Carbon Catalyst 1389.2.1.2 Pd and Pt 1459.2.2 Transition Metal Catalysts 1459.2.3 Metal-Free Catalysts 1499.3 Hydrogen Peroxide Synthesis 1549.3.1 Catalysts Advances 1549.3.1.1 Pure Metals 1549.3.1.2 Metal Alloys 1569.3.1.3 Carbon Materials 1579.3.1.4 Electrodes and Reaction Cells 158References 16110 Fuel Cell and Metal-Air Battery 16710.1 H2 Fuel Cell 16710.2 Metal-Air Battery 17010.2.1 Metal-Air Battery Structure 171References 181Part VI Small Organic Molecules Oxidation and Device 18311 Introduction 18511.1 Primary Measurement Methods and Parameters 18611.1.1 Primary Measurement Methods 18611.1.2 Primary Parameter 193References 19712 C1 Molecule Oxidation 19912.1 Methane Oxidation 19912.1.1 Reaction Mechanism 19912.1.1.1 Solid–Liquid–Gas Reaction System 19912.1.2 Acidic Media 19912.1.3 Alkaline or Neutral Media 20112.2 Methanol Oxidation 20312.2.1 Reaction Thermodynamics and Mechanism 20312.2.2 Catalyst Advances 20412.2.2.1 Pd-Based Catalysts 20412.2.2.2 Pt-Based Catalysts 20812.2.2.3 Platinum-Based Nanowires 20812.2.2.4 Platinum-Based Nanotubes 21012.2.2.5 Platinum-Based Nanoflowers 21212.2.2.6 Platinum-Based Nanorods 21412.2.2.7 Platinum-Based Nanocubes 21512.2.3 Pt–Ru System 21712.2.4 Pt–Sn Catalysts 21812.3 Formic Acid Oxidation 21912.3.1 Reaction Mechanism 21912.3.2 Catalyst Advances 22012.3.2.1 Pd-Based Catalysts 22012.3.2.2 Pt-Based Catalysts 223References 22613 C2+ Molecule Oxidation 23513.1 Ethanol Oxidation 23513.1.1 Reaction Mechanism 23513.1.2 Catalyst Advances 23513.1.2.1 Pd-Based Catalysts 23513.1.2.2 Pt-Based Catalysts 23913.1.2.3 Pt–Sn System 24313.2 Glucose Oxidase 25013.3 Ethylene Glycol Oxidation 25113.4 Glycerol Oxidation 251References 25414 Fuel Cell Devices 25714.1 Introduction 25714.2 Types of Direct Liquid Fuel Cells 25814.2.1 Acid and Alkaline Fuel Cells 25814.2.2 Direct Methanol Fuel Cells (DMFCs) 26014.2.3 Direct Ethanol Fuel Cells (DEFCs) 26114.2.4 Direct Ethylene Glycol Fuel Cells (DEGFCs) 26114.2.5 Direct Glycerol Fuel Cells (DGFCs) 26214.2.6 Direct Formic Acid Fuel Cells (DFAFCs) 26214.2.7 Direct Dimethyl Ether Fuel Cells (DDEFCs) 26314.2.8 Other DLFCs 26314.2.9 Challenges of DLFCs 26414.2.10 Fuel Conversion and Cathode Flooding 26414.2.11 Chemical Safety and By-product Production 26514.2.12 Unproven Long-term Durability 265References 267Part VII CO2 Reduction and Device 27115 Introduction 27315.1 Basic Parameters of the CO2 Reduction Reaction 27615.1.1 The Fundamental Parameters to Evaluate the Catalytic Activity 27615.1.1.1 Overpotential (;;) 27615.1.1.2 Faradaic Efficiency (FE) 27615.1.1.3 Current Density ( j) 27715.1.1.4 Energy Efficiency (EE) 27715.1.1.5 Tafel Slope 27815.1.2 Factors Affecting ECDRR 27815.1.2.1 Solvent/Electrolyte 27815.1.2.2 pH 28015.1.2.3 Cations and Anions 28115.1.2.4 Concentration 28215.1.2.5 Temperature and Pressure Effect 28215.1.3 Electrode 28315.1.3.1 Loading Method 28315.1.3.2 Preparation 28415.1.3.3 Experimental Process and Analysis Methods 284References 28516 Electrocatalysts-1 28916.1 Heterogeneous Electrochemical CO2 Reduction Reaction 28916.2 Thermodynamic and Kinetic Parameters of Heterogeneous CO2 Reduction in Liquid Phase 28916.2.1 Bulk Metals 29316.2.2 Nanoscale Metal and Oxidant Metal Catalysts 29416.2.2.1 Gold (Au) 29516.2.2.2 Silver (Ag) 29616.2.2.3 Palladium (Pd) 29716.2.2.4 Zinc (Zn) 29816.2.2.5 Copper (Cu) 29916.2.3 Bimetallic/Alloy 301References 30617 Electrocatalysts-2 30917.1 Single-Atom Metal-Doped Carbon Catalysts (SACs) 30917.1.1 Nickel (Ni)-SACs 30917.1.2 Cobalt (Co)-SACs 31117.1.3 Iron (Fe)-SACs 31117.1.4 Zinc (Zn)-SACs 31417.1.5 Copper (Cu)-SACs 31417.1.6 Other 31617.2 Metal Nanoparticles-Doped Carbon Catalysts 31717.3 Porous Organic Material 32017.3.1 Metal Organic Frameworks (MOFs) 32017.3.2 Covalent Organic Frameworks (COFs) 32117.3.3 Metal-Free Catalyst 32217.4 Metal-Free Carbon-Based Catalyst 32217.4.1 Other Metal-Free Catalyst 32417.5 Electrochemical CO Reduction Reaction 32417.5.1 The Importance of CO Reduction Study 32417.5.2 Advances in CO Reduction 326References 32718 Devices 33118.1 H-Cell 33118.2 Flow Cell 33318.3 Requirements and Challenges for Next-Generation CO2 Reduction Cell 33818.3.1 Wide Range of Electrocatalysts 33818.3.2 Fundamental Factor Influencing the Catalytic Activity for ECDRR 33918.3.3 Device Engineering 340References 342Part VIII Computations-Guided Electrocatalysis 34519 Insights into the Catalytic Process 34719.1 Electric Double Layer 34719.2 Kinetics and Thermodynamics 34919.3 Electrode Potential Effects 350References 35220 Computational Electrocatalysis 35520.1 Computational Screening Toward Calculation Theories 35620.2 Reactivity Descriptors 35820.2.1 d-band Theory Motivates Electronic Descriptor 35920.2.2 Coordination Numbers Motives Structure Descriptor 36120.3 Scaling Relationships: Applications of Descriptors 36120.4 The Activity Principles and the Volcano Curve 36320.5 DFT Modeling 36620.5.1 CHE Model 36720.5.2 Solvation Models 36820.5.3 Kinetic Modeling 371References 37421 Theory-Guided Rational Design 37721.1 Descriptors-Guided Screening 37721.2 Scaling Relationship-Guided Trends 38021.2.1 Reactivity Trends of ECR 38021.2.2 Reactivity Trends of O-included Reactions 38221.2.3 Reactivity Trends of H-included Reactions 38521.3 DOS-Guided Models and Active Sites 386References 38822 DFT Applications in Selected Electrocatalytic Systems 39122.1 Unveiling the Electrocatalytic Mechanism 39122.1.1 ECR Reaction 39322.1.2 OER Reaction 39422.1.3 ORR Reaction 39622.1.4 HER Reaction 39722.1.5 HOR Reaction 39822.1.6 CO Oxidation Reaction 40022.1.7 FAOR Reaction 40222.1.8 MOR Reaction 40222.1.9 EOR Reaction 40422.2 Understanding the Electrocatalytic Environment 40622.2.1 Solvation Effects 40622.2.2 pH Effects 40922.3 Analyzing the Electrochemical Kinetics 41022.4 Perspectives, Challenges, and Future Direction of DFT Computation in Electrocatalysis 413References 414Part IX Potential of In Situ Characterizations for Electrocatalysis 421References 42223 In Situ Characterization Techniques 42323.1 Optical Characterization Techniques 42323.1.1 Infrared Spectroscopy 42323.1.2 Raman Spectroscopy 42423.1.3 UV–vis Spectroscopy 42623.2 X-Ray Characterization Techniques 42723.2.1 X-Ray Diffraction (XRD) 42923.2.2 X-Ray Absorption Spectroscopy (XAS) 42923.2.3 X-Ray Photoelectron Spectroscopy (XPS) 43123.3 Mass Spectrometric Characterization Techniques 43123.4 Electron-Based Characterization Techniques 43223.4.1 Transmission Electron Microscopy (TEM) 43423.4.2 Scanning Probe Microscopy (SPM) 434References 43624 In Situ Characterizations in Electrocatalytic Cycle 44124.1 Investigating the Real Active Centers 44124.1.1 Monitoring the Electronic Structure 44224.1.2 Monitoring the Atomic Structure 44424.1.3 Monitoring the Catalyst Phase Transformation 44624.2 Investigating the Reaction Mechanism 44924.2.1 Through Adsorption/Activation Understanding 45024.2.2 Through Intermediates In Situ Probing 45124.2.3 Through Catalytic Product In Situ Detections 45424.3 Evaluating the Catalyst Stability/Decay 45724.4 Revealing the Interfacial-Related Insights 46024.5 Conclusion 462References 462Part X Electrochemical Catalytic Carbon Cycle 465References 46625 Electrochemical CO2 Reduction to Fuels 467References 47926 Electrochemical Fuel Oxidation 483References 49527 Evaluation and Management of ECC 49927.1 Basic Performance Index 49927.2 CO2 Capture and Fuel Transport 50027.3 External Management 50027.4 General Outlook 502References 505Index 507