Towards Artificial Photosynthesis: Exploration of Efficient First-Row Transition Metal-Based Water Oxidation Catalysts

Sammanfattning: Artificial photosynthesis provides a promising strategy for sustainable energy harvesting, yet its overall efficiency is limited by the water oxidation reaction. The subject of this thesis focuses on the exploration of highly efficient cost-effective heterogeneous catalysts for water oxidation, and the investigation of essential catalyst structure-activity relationships.Chapters 1 and 2 present a brief introduction on heterogeneous catalysts for water oxidation, including selected state-of-the-art catalysts, methodologies for activity improvement, and mechanistic investigations. The characterization methods used in this thesis are also demonstrated.In chapter 3, a molecular functionalization approach is developed to rationally modify the electronic structure of NiO catalyst, by which the water oxidation activity is systematically tailored. These studies correspond to the question: “How to rationally adjust the catalytic performance of heterogeneous catalysts?”In chapter 4, to lower the catalyst cost, a Fe-based Fe0.65Cr0.35Ox nanocatalyst is fabricated by structural and electronic modulation, which shows considerable water oxidation activity. These studies target the question: “How to fabricate an efficient Fe-based water oxidation catalyst?”In chapter 5, a bio-inspired Mn-based catalyst is presented. The catalyst successfully imitates the key features of the natural oxygen evolving complex, achieving dramatically improved water oxidation activity. These studies correspond to the question: “How to improve the catalytic activity of Mn-based water oxidation catalysts?”Finally, in chapter 6, a 3D NiFeCr/Cu nanoarray electrode is constructed by structural engineering, which exhibits extremely high water oxidation activity. These studies correspond to the question: “How to fabricate an efficient catalytic electrode for water oxidation?”