검색 상세

Optimization of Metal Oxide Anodes via Co- catalyst and Doping Approaches for Water Splitting based Sustainable Hydrogen Production

초록/요약

Optimization of Metal Oxide Anodes via Co-catalyst and Doping Approaches for Water Splitting based Sustainable Hydrogen Production By Rana Basit Ali Doctor of Philosophy in Engineering Graduate School of Ajou University Advised by Prof. Hyungtak Seo, Ph.D. The worldwide desire for clean and environmentally friendly energy solutions is rapidly developing, especially within the context of the current environmental crisis and the depleting supplies of fossil fuels. Hydrogen has emerged as a possible alternative energy source due to its substantial energy content and its characteristic that it generates water as the sole byproduct when utilized as fuel. However, the fundamental problem lies in manufacturing hydrogen in an efficient, economical, and ecologically benign manner. Photoelectrochemical (PEC) water splitting is a highly appealing option, as it simply uses solar energy to split the water producing hydrogen and oxygen. However, the effectiveness of PEC devices is currently limited by reasons such as inadequate light absorption, recombination of charges, and sluggish surface reaction kinetics. Essential to these investigations is the important function of anode materials, which significantly impact the efficiency, stability, and kinetics of water oxidation reactions. The earliest investigations were centered on PEC water splitting, utilizing customized anode materials to maximize light absorption, charge carrier separation, and catalytic performance. Doping and co-catalyst integration were applied to change the structural, electrical, and surface properties of photoanodes, resulting in increased photoelectrochemical stability and enhanced hydrogen production rates. These investigations demonstrated that the creation of resilient and efficient anodes is important to overcoming material degradation and enhancing the overall performance of PEC systems. In addition to PEC water splitting, my study into electrochemical (EC) overall water splitting has implications in establishing a consistent and scalable technique of hydrogen production. EC systems do not rely on solar irradiation, enabling for continuous hydrogen generation when driven by the renewable energy sources including wind or hydroelectric power. This finding is essential because it gives a complementary option to PEC water splitting, enabling an efficient hydrogen generating system irrespective of an absence of sunlight with continued emphasis on optimizing anode materials for oxygen evolution reaction (OER) kinetics. The EC studies focused on the synthesis and characterization of a novel, stable and highly active electrocatalyst capable of supporting overall water splitting, specifically for alkaline water splitting. Furthermore, by focusing on altering material characteristics that enhance both oxygen (OER) and hydrogen evolution (HER) reactions in EC water splitting, this research offers up prospects for connecting such systems to the renewable energy grids, which will lead to more sustainable energy infrastructures. The combination of PEC and EC techniques to hydrogen generation allows this research vital for solving simultaneous short-term material concerns and long-term sustainability objective in the worldwide energy landscape.

more

목차

Chapter 1. Introduction 1
1.1. Overview of Water Splitting 1
1.1.1. Importance of Sustainable Hydrogen Production 1
1.1.2. Role of Anodes in Water Splitting 2
1.1.2.1. Role in PEC water splitting 2
1.1.2.2. Role in EC Water Splitting 3
1.2. Photoelectrochemical (PEC) vs Electrochemical (EC) Water Splitting 5
1.2.1. Photoelectrochemical (PEC) Water Splitting 6
1.2.2. Electrochemical (EC) Water Splitting 6
1.2.3. Comparison of PEC and EC Water Splitting 9
1.3. Scope and Necessity of the Research 11
1.3.1. Objectives of the Research 12
1.4. Dissertation outline 13
1.5. Related publications 18
Chapter 2. Literature review 19
2.1. Metal Oxides as Anode Materials 19
2.1.1. Common Metal Oxide-based Photoelectrodes Materials in PEC Water Splitting 19
2.1.1.1. Role of Binary Transition Metal-based Oxides as Photoanodes 23
2.1.2. Common Metal Oxide-based Electrode Materials in EC Water Splitting 31
2.1.2.1. Metal Oxides Electrocatalysts for Oxygen Evolution Reaction (OER) 34
2.1.2.2. Vanadium Oxide (V) based Electrocatalysts for OER 35
2.2. Co-catalyst and Doping Strategies. 39
2.2.1. LDHs Co-catalysts coupling for TiO2 40
2.2.2. Doping Strategies for Enhanced PEC and EC of WO3 and VOx based Materials 43
2.3. Recent Advances in PEC and Electrolysis for Water Splitting 47
Chapter 3. 1D TiO2 with FeNiOOH Cocatalyst for PEC Water Splitting 49
3.1. Introduction 49
3.2. Experimental Methods 52
3.2.1. Synthesis of titanium dioxide nanorods (TiO2 NRs) 52
3.2.2. Electrodeposition of FeNiOOH cocatalyst on TiO2 NRs photoanode. 52
3.2.3. Characterization 53
3.2.4. Photoelectrochemical (PEC) measurements 54
3.3. Results and discussion 55
3.3.1. Structural morphology of TiO2 NRs and TiO2/FeNiOOH photoelectrode 55
3.3.2. Spectroscopic characterization of TiO2/FeNiOOH thin films 61
3.3.3. PEC water-splitting performance of TiO2/FeNiOOH photoelectrode. 63
3.3.4. Band- edge insights for TiO2 and TiO2/FeNiOOH photoelectrodes. 67
3.4. Summary 71
Chapter 4. Doping of WO3 with Pb, Sr, and Ce Metals for Enhanced PEC Water Splitting 72
4.1. Pb-doped WO3 for PEC Water Splitting 72
4.1.1. Introduction 72
4.1.2. Experimental Methods 75
4.1.2.1. Fabrication of undoped and Pb-doped WO3 thin films 75
4.1.2.2. Characterizations 76
4.1.2.3. Electrochemical measurements 77
4.1.2.4. DFT studies 78
4.1.3. Results and discussion 79
4.1.3.1. Fabrication and characterization of WO3 and Pb-WO3 films 79
4.1.3.2. Crystallographic structure of undoped and Pb-doped WO3 81
4.1.3.3. Spectroscopic properties of undoped and Pb-doped WO3. 85
4.1.3.4. Photoelectrochemical (PEC) water splitting properties 88
4.1.3.5. Stability and band edge properties 92
4.1.3.6. DFT calculations 96
4.1.4. Summary 100
4.2. Sr-doped WO3 for PEC Water Splitting 102
4.2.1. Introduction 102
4.2.2. Experimental Methods 106
4.2.2.1. Materials for wet synthesis 106
4.2.2.2. Fabrication of thin films 106
4.2.2.3. Analytical instrumentations 107
4.2.2.4. Photoelectrochemical (PEC) measurements 108
4.2.2.5. DFT studies 109
4.2.3. Results and discussion 110
4.2.3.1. Synthesis and surface characterizations of photoanodes 110
4.2.3.2. Crystallographic analysis 112
4.2.3.3. Spectroscopic analysis 115
4.2.3.4. Photoelectrochemical (PEC) analysis 119
4.2.3.5. Application in organic waste treatment and the band edge properties of Sr-doped WO3 126
4.2.3.6. DFT analysis 131
4.2.4. Summary 135
4.3. Ce-doped WO3 for PEC Water Splitting 136
4.3.1. Introduction 136
4.3.2. Experimental methods 139
4.3.2.1. Synthesis of undoped and doped tungsten oxide nanorods (WO3 NRs) 139
4.3.2.2. Instrumentation 139
4.3.2.3. Data description and feature selection 140
4.3.2.4. Development of multi-head attention transformer model for dopant selection 142
4.3.2.5. Proposed dopant selection methodology 144
4.3.3. Experimental methods 147
4.3.3.1. Estimation performance of MAT model for dopant selection 147
4.3.3.2. Physical and electrochemical characterization of synthesized photoanodes 152
4.3.3.3. DFT analysis of fabricated electrodes 169
4.3.4. Summary 172
Chapter 5. Transition from PEC to Electrolysis: 2D SrVO Electrocatalyst for Overall Water Splitting 173
5.1. Introduction 173
5.2. Experimental Methods 177
5.2.1. Materials and chemicals 177
5.2.2. Fabrication of the 2D vanadate electrodes 178
5.2.3. Nomenclature of synthesized materials 179
5.2.4. Characterization techniques 179
5.2.5. Electrochemical measurements 180
5.2.6. Computational methods 181
5.3. Results and discussion 182
5.3.1. Fabrication, morphological, and structure characterization of synthesized SrVO and Fe-SrVO electrodes 182
5.3.2. Electrochemical oxygen evolution reaction (OER) performance 190
5.3.3. Electrochemical hydrogen evolution reaction (HER) performance 198
5.3.4. Density functional theory (DFT) calculations 201
5.4. Summary 206
Chapter 6. Conclusions and Future Aspects 207
Bibliography 210

more
반출 Meta View 목록