Foreword xi

Preface xiii

1 Introduction of the Metastable-Phase Materials 1
Qi Shao and Mingwang Shao

1.1 Introduction 1

1.2 What Are Metastable-Phase Materials? 1

1.3 The Categories of Metastable-Phase Materials 2

1.4 The Influence on Polymorphs of Materials 6

1.5 The Wide Applications of Metastable-Phase Materials 8

1.6 The Criterion for Stable-Phase and Metastable-Phase Materials 8

References 10

2 Synthetic Methodology 15
Qi Shao

2.1 Introduction 15

2.2 The Key for Synthesizing Metastable-Phase Materials 15

2.3 The Synthetic Methods for Synthesizing Metastable-Phase Materials 16

References 25

3 Characterization 33
Qi Shao

3.1 Introduction 33

3.2 Characterizations 33

3.3 How to Determine the Phase of Metastable-Phase 2D Metal Oxides 43

References 45

4 Metastable-Phase Metals 51
Qi Shao

4.1 Introduction 51

4.2 Noble Metals 51

4.3 Non-noble Metals 60

4.4 The Criterion to Determine the Stable-Phase and Metastable-Phase Metals 64

References 66

5 Metastable-Phase Oxide, Chalcogenide, Phosphide, and Boride Materials 71
Qi Shao

5.1 Introduction 71

5.2 Oxides 71

5.3 Chalcogenides 76

5.4 Others 78

References 80

6 Spin-Dependent Metastable-Phase Materials 85
Qi Shao

6.1 Introduction 85

6.2 Spin-Related Catalysis 85

6.3 Spin-Related Catalysts for Alkaline OER 88

6.4 Spin-Related Catalyst for Acidic OER 89

References 90

7 Crystallography, Design, and Synthesis of Two-Dimensional Metastable-Phase Oxides 93
Mingwang Shao and Qi Shao

7.1 Introduction 93

7.2 The Point Group, Crystal System, Crystal Lattice, and Space Groups of 2D Materials 93

7.3 The Possible Crystal Structures and Chemical Formula of 2D Metal Oxides 100

7.4 How to Prepare Metastable-Phase 2D Metal Oxides 119

7.5 2D Metastable-Phase Noble Metal Oxides 120

7.6 Metastable-Phase 2D Non-noble Metal Oxides 126

7.7 The Covalent Bond Behavior in Metastable-Phase 1T Metal Oxides 129

References 134

8 Electrocatalysis 141
Qi Shao

8.1 Introduction 141

8.2 Several Typical Electrochemical Reactions 141

8.3 Metastable-Phase Catalysts for Advanced Electrocatalysis 145

References 167

9 Photocatalysis 173
Mingwang Shao and Zhenhui Kang

9.1 Introduction 173

9.2 Fundamental Concepts of Photocatalysis 173

9.3 Metastable-Phase Catalysts and Photocatalysis 177

9.4 The Advantages and Disadvantages of Photocatalysis 182

References 183

10 Thermocatalysts 191
Qi Shao

10.1 Introduction 191

10.2 Several Typical Thermocatalytic Reactions 191

10.3 Metastable-Phase Catalysts for Thermocatalysis 193

References 201

Summary and Outlook 207

Index 209

Qi Shao, Ph D, is an associate professor at the College of Chemistry, Chemical Engineering and Materials Science, Soochow University, China. She received her Ph D in applied physics from City University of Hong Kong in 2016.
Zhenhui Kang, Ph D, is currently a professor at the Institute of Functional Nano & Soft Materials (FUNSOM) and the Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices in Soochow University, China.
Mingwang Shao, Ph D, is a professor at the Institute of Functional Nano & Soft Materials (FUNSOM) and the Jiangsu Key Laboratory for Cabon-Based Functional Materials and Devices, Soochow University, China. He received his Ph D from the University of Science and Technology of China in 2003.