Non-oxide electrocatalysts for energy-saving hybrid water electrolysis systems

Replacing thermodynamically unfavorable oxygen evolution with small molecule oxidation can reduce the energy input of water electrolysis while co-producing value-added chemicals. Hybrid Water Electrolysis: Non-Oxide Electrocatalysts in Small Molecule Oxidation, written by a team of electrochemistry and catalysis researchers from four countries, provides detailed coverage of functional electrocatalysts -- metal sulfides, carbides, nitrides, phosphides, and single atom catalysts --applied to this coupled approach.

The book examines nanostructured electrocatalytic materials developed via pulsed laser techniques and their deployment in hybrid electrolyzers for hydrogen fuel production alongside oxidation of benzyl alcohol, methanol, ethanol, urea, hydrazine, furfural, and formic acid. Coverage includes reaction mechanisms, governing principles for catalytic behavior, stability analysis, and an assessment of challenges and opportunities for scaling these systems to industrial application.

Readers will also find:

• Detailed discussion of metal sulfide, carbide, nitride, and phosphide electrocatalysts and their catalytic mechanisms in small molecule oxidation reactions
• Case studies illustrating how hybrid electrolyzer configurations simultaneously produce hydrogen fuel and value-added chemical products at reduced energy cost
• Analysis of single atom catalysts and their role in enhancing selectivity and activity for coupled electrolysis processes
• Coverage of pulsed laser synthesis techniques for fabricating nanostructured electrocatalytic materials with controlled morphology and composition
• Assessment of scale-up challenges and industrial opportunities for transitioning hybrid water electrolysis from laboratory to commercial deployment

Designed for catalytic chemists, surface chemists, physical chemists, inorganic chemists, and chemical engineers, this reference delivers the mechanistic detail and materials science coverage required to advance non-oxide electrocatalyst development for hybrid water electrolysis and sustainable hydrogen production.

List of Contributors xv

About the Editors xxi

Preface xxiii

Part I Fundamental 1

1 Fundamentals and Advantages of Hybrid Water Electrolysis 3
Vipada Aupama, Phonnapha Tangthuam, Ahmad Azmin Mohamad, and Soorathep Kheawhom

1.1 Concept and Scope 3

1.2 Thermodynamic and Kinetic Basis for Energy Reduction 7

1.3 Anodic Reaction Space and Substrate Selection 9

1.4 Advantages Beyond Voltage: Coproduction, Safety, and Sustainability 13

1.4.1 Coproduction: Transforming the Anode into a Chemical Manufacturing Module 14

1.4.2 Safety and Operational Flexibility: Reducing Oxygen-related Constraints 14

1.4.3 Sustainability and Circularity: Coupling Hydrogen with Waste Conversion 15

1.4.4 Interdependence of Advantages and the Role of System-level Metrics 16

1.5 Remaining Challenges and Outlook 16

References 19

Part II Alcohol-assisted Water Electrolysis 23

2 Metal Carbides and Nitrides Electrocatalysts for Alcohol-assisted Water Electrolysis 25
Phonnapha Tangthuam, Vipada Aupama, Ahmad Azmin Mohamad, and Soorathep Kheawhom

2.1 Background and Scope 25

2.2 Intrinsic Properties Governing Electrocatalytic Activity 27

2.3 Catalytic Roles in Alcohol-assisted Electrolysis Systems 29

2.3.1 Cathode: HER 30

2.3.2 Anode: AOR 30

2.4 Surface Dynamics and Stability Under Operating Conditions 31

2.4.1 Surface Reconstruction as Activation and Degradation 32

2.4.2 Oxidation, Corrosion, and the Conductive-core/Active-shell Picture 33

2.4.3 Adsorbate-driven Effects and Selectivity Drift 33

2.4.4 Defects, Vacancies, and Stability-Activity Trade-offs 34

2.4.5 Electrode-level Stability 34

2.4.6 Assessing Stability in Hybrid Electrolysis 34

2.4.7 Design Implications 35

2.5 Reaction Pathways and Product Selectivity in Alcohol Oxidation 35

2.5.1 Elementary Steps and Pathway Competition 35

2.5.2 Adsorption Energetics as a Selectivity Lever 36

2.5.3 Surface Oxygenated Species and Reconstructed States 36

2.5.4 Poisoning, Carbon Balance, and Long-term Selectivity 36

2.5.5 Multicomponent Carbides and Nitrides in Selectivity Tuning 37

2.5.6 Selectivity Metrics and Benchmarking 37

2.6 Engineering Strategies to Enhance Performance 37

2.6.1 Nanostructuring and Hierarchical Porosity 38

2.6.2 Morphology and Surface Termination Control 39

2.6.3 Defect and Vacancy Engineering 39

2.6.4 Heteroatom Doping 39

2.6.5 Multicomponent Carbides and Nitrides 39

2.6.6 Heterostructures and Interfaces 40

2.6.7 Conductive Scaffolds and Self-supported Electrodes 40

2.6.8 Electrode Architecture and Transport 40

2.6.9 Benchmarking During Engineering Optimization 40

2.7 Comparative Summary of Carbides vs. Nitrides 40

2.8 Outlook and Remaining Challenges 41

References 44

3 Single-atom Electrocatalysts for Alcohol-assisted Water Electrolysis 47
P. Keerthana, Soorya S. Raj, and M. L. Aruna Kumari

3.1 Introduction 47

3.2 Fundamentals of AAWE 49

3.2.1 Methanol-assisted Hydrogen Production 50

3.2.2 Ethanol-assisted Hydrogen Production 51

3.2.3 Propanol-assisted Hydrogen Production 52

3.2.4 Glycerol-assisted Hydrogen Production 52

3.3 SAECs: Concept and Design Principles 53

3.3.1 NM-SACs 54

3.3.2 SACs@ATMs 55

3.4 Synthesis Strategies of SAECs 58

3.4.1 Bottom-up Methods 58

3.4.1.1 Atomic Layer Deposition Method 58

3.4.1.2 Electrodeposition Method 59

3.4.1.3 Pyrolysis-assisted Method 60

3.4.1.4 Wet-chemical Synthesis 61

3.4.2 Top-down Method 62

3.5 Integration of SAECs into AAWE 63

3.6 Challenges and Perspectives 67

3.7 Conclusion 69

References 69