Carbon Dioxide Electrochemistry: Homogeneous and Heterogeneous Catalysis

Cover
Preface
Contents
Preface
Contents
1 Approaches to Controlling Homogeneous Electrochemical Reduction of Carbon Dioxide
1.1 Introduction
1.2 Overview of Parameters for Evaluating Electrocatalysts
1.3 Overview of Metals Utilized in Electrochemical CO2 Reduction
1.3.1 Group 6
1.3.2 Group 7
1.3.3 Group 8
1.3.4 Group 9
1.3.5 Group 10
1.4 Brønsted Acid Source
1.5 Pendent Proton Shuttles
1.6 Through Space Effects
1.7 Lewis Acid and Base Additives
1.8 Cooperativity in Multinuclear Metal Systems
1.9 Overpotential – Activity Relationship
1.10 Selective Formate Production
1.11 Catalyst Comparison
1.12 Future Outlook and Recommendations
Acknowledgements
References
2 Homogeneous Electrochemical Reduction of CO2. From Homogeneous to Supported Systems
2.1 Introduction
2.2 Immobilization of Molecular Catalysts and Creation of Single-atom Catalysts
2.2.1 Support Material
2.2.2 Methods for Immobilization of Molecular Catalysts
2.2.3 Single-atom Catalysts: Bridging Molecular Supported Catalysis and Electrocatalysis
2.3 Characterization and Performance of Assemblies
2.4 Toward Kinetic and Mechanistic Characterization of Supported Systems
2.4.1 Introduction
2.4.2 General Considerations for Kinetic Analysis of Supported Systems
2.4.3 Insights into Mechanisms for CO2 Reduction
2.4.4 Toward Improved Efficiency
References
3 Heterogeneous Electrochemical CO2 Reduction
3.1 Introduction
3.2 Electrocatalyst
3.2.1 Aqueous CO2 Chemistry
3.2.2 Selectivity Trends
3.2.3 Activating Carbon Dioxide
3.2.4 Carbon Monoxide Evolution Over Silver and Gold
3.2.5 Enhancing Carbon Monoxide Evolution Activity
3.2.6 Distribution of Products Formed Over Polycrystalline Copper
3.2.7 CO as the Intermediate to Hydrocarbons and Alcohols
3.2.8 Reversibly Adsorbed CO
3.2.9 Dependence of Methane and Ethene Evolution Activity on Surface Atomic Structure
3.2.10 Dependence of Methane and Ethene Evolution Activity on Electrolyte pH
3.2.11 Mechanism of CO Methanation
3.2.12 Mechanisms of C–C Coupling
3.2.13 Aldehydes as Intermediates to Primary Alcohols
3.2.14 Aldehydes as Intermediates to the Conjugate Bases of Carboxylic Acids
3.2.15 Modifying the Selectivity of Copper
3.3 Electrolyte
3.3.1 Concentration Polarization
3.3.2 Impact of Electrochemical Cell Hydrodynamics
3.3.3 Impact of Buffer Concentration and Acidity
3.3.4 Impact of Cation Size
3.4 Conclusions
References
4 Nanostructures for CO2 Reduction: From Theoretical Insight to Material Design
4.1 Introduction
4.2 Theoretical Insights in Electrochemical CO2 Reduction
4.2.1 Reaction Complexity
4.2.2 Reaction Paths and Intermediates
4.2.3 CO2RR Descriptors
4.2.4 CORR Descriptors
4.3 Nanostructured Mono-metallic Catalysts
4.3.1 Nanostructured Au Catalysts
4.3.2 Nanostructured Ag Catalysts
4.3.3 Nanostructured Cu Catalystsz
4.4 Nanostructured Bi-metallic Catalystsy
4.4.1 Cu–Pd/Pt Catalysts
4.4.2 Cu–In/Sn Catalysts
4.4.3 Cu–Au/Ag/Zn Catalysts
4.5 Activity Comparison
4.6 Summary and Outlook
Acknowledgements
References
5 Theoretical Approach to Homogeneous Catalytic Reduction of CO2: Mechanistic Understanding to Build New Catalysts
5.1 Introduction
5.1.1 Difficulty in CO2 Reduction
5.1.2 Present Status: Organo-catalysts and Transition Metal-based Homogeneous and Heterogeneous CO2 Reduction
5.2 Theoretical Background
5.2.1 Potential Energy Surface and Reaction Energetics
5.2.2 Relating Thermodynamics and Kinetics: Bell–Evans–Polanyi (BEP) Principle
5.2.3 Computational Methodology
5.2.4 Calculation of Hydricity
5.2.5 Calculation of Standard Reduction Potential and pKa
5.3 Case Studies: Non-noble Metal Catalysed Homogeneous CO2 Reduction
5.3.1 CO2 Reductive Dissociation
5.3.2 CO2 Hydrogenation
5.4 Summary and Future Outlook
References
6 Bridging Homogeneous and Heterogeneous Systems: Atomically Dispersed Metal Atoms in Carbon Matrices for Electrocatalytic CO2 Reduction
6.1 Introduction
6.1.1 Bridging Homogeneous and Heterogeneous Catalysts
6.1.2 Carbon-based Electrocatalysts
6.2 Preparation of Carbon-based Atomically Dispersed Metal Catalysts
6.2.1 Atomic Layer Deposition
6.2.2 Wet Chemistry Process
6.2.3 Pyrolysis at High Temperature
6.2.4 Graphite-conjugated Catalysts
6.3 Characterization of Atomically-dispersed Metal Catalysts
6.3.1 Identification of Atomically-dispersed Metal Atoms
6.3.2 In Situ/Operando Measurement Techniques
6.4 Structure and Activity of Atomically-dispersed Metal Catalysts
6.4.1 Structure of Dispersed Metal Atoms on Carbon Supports
6.4.2 CO2 Reduction Activities of Atomically-dispersed Metal Catalysts
6.4.3 Metal Active Sites with Low Coordination Number
6.4.4 Metal Active Sites with Carbon Coordination
6.4.5 Metal Active Sites with Axial Coordination
6.4.6 Effect of Second Coordination Sphere (SCS): Inductive Effect
6.4.7 Effect of SCS: Local Proton Environment
6.4.8 Effect of the Oxidation State of the Metal Centre
6.5 Production of Highly-reduced C1 and Multi-carbon Products
6.5.1 Production of C1 Hydrocarbons
6.5.2 Production of Multi-carbon Products
6.6 Conclusions
References
7 Bridging Homogeneous and Heterogeneous Systems— Photoelectrodes for CO2 Electrochemical Conversion
7.1 Introduction
7.2 The Physicochemical Process at the Semiconductor Photoelectrode
7.2.1 The Semiconductor/Electrolyte Junction
7.2.2 The Buried Junction
7.3 Co-catalyst Selection for CO2 Reduction
7.3.1 Heterogeneous Catalysts
7.3.2 Molecular Catalysts
7.3.3 Enzyme Catalysts
7.4 Electrolyte Solution Selection
7.4.1 Solvent
7.4.2 Electrolyte
7.4.3 Additives
7.5 Summary
References
8 Hybrid Biological–Inorganic Systems for CO2 Conversion to Fuels
8.1 Introduction
8.2 Carbon Fixation Cycles
8.2.1 Aerobic Carbon Fixation
8.2.2 Anaerobic Carbon Fixation
8.3 Efficiency Metrics
8.4 Classes of Hybrid Biological–Inorganic (HBI) Systems
8.4.1 Direct H2 HBI Systems
8.4.2 Indirect H2 HBI Systems
Organic Mediators
8.4.3 Electron Transfer HBI Systems
8.5 Conclusions
Abbreviations
Acknowledgements
References
9 Spectroscopic Methods to Study Electrochemical CO2 Reduction
9.1 Introduction
9.2 Vibrational Spectroscopy for the Investigation of Electrochemical CO2 Reduction
9.2.1 Infrared Spectroscopy
9.2.2 Raman Spectroscopy
9.3 X-ray Absorption Spectroscopy for the Investigation of Electrochemical CO2 Reduction
9.3.1 Application in Heterogeneous Systems
9.3.2 Application in Homogeneous Systems
9.4 UV–Vis Spectroscopy for the Investigation of Electrochemical CO2 Reduction
9.4.1 Application in Homogeneous Systems
9.5 Summary and Outlook
References
10 Electrochemical Reactors
10.1 Introduction
10.2 Differentiated CO2RR Chemistry in an H-Cell and Flow Reactor
10.3 Catalyst Testing at High Current Densities
10.4 Flow Reactor Architectures
10.5 Membranes
10.5.1 Anion Exchange Membranes
10.5.2 Cation Exchange Membranes
10.5.3 Bipolar Membranes
10.6 Gas Diffusion Electrodes
10.6.1 Gas Diffusion Layers
10.6.2 Gas Diffusion Electrode Structure and Function
10.6.3 Water Management
10.7 Conclusions
References
Subject Index