| Author: | Wu, Tong |
| Title: | First-principles studies of transition metals based nanomaterials for electrocatalysis of sustainable energy-related electrochemical reactions |
| Advisors: | Huang, Bolong (ABCT) Yung, Ka-fu Joseph (ABCT) |
| Degree: | Ph.D. |
| Year: | 2024 |
| Subject: | Nanostructured materials Electrocatalysis Renewable energy sources Hong Kong Polytechnic University -- Dissertations |
| Department: | Department of Applied Biology and Chemical Technology |
| Pages: | 149 pages : color illustrations |
| Language: | English |
| Abstract: | The ever-growing world population and excessive exploitation of natural resources have resulted in various environmental and energy crises. The significance of sustainable lifestyle and renewable energy resources has been widely acknowledged today. Scientists are striving for reducing the usage of fossil fuels in economic activities and finally completely replacing them with clean and sustainable energy resources. Considerable research interest has been attracted by the exploration of advanced energy conversion and storage systems including water splitting, carbon reduction reaction, nitrogen fixation and fuel cells as promising solutions for the aforementioned challenge. One notable example is fuel cell technology, renowned for its superior energy conversion efficiency and emission-free operation. Another promising avenue lies in the electrolysis of water, a method that holds considerable promise in the production of hydrogen, a critical candidate among sustainable energy resources. Theoretically, the entire cycle of energy production and consumption could be rendered carbon emission-free provided it is powered by renewable electricity resources, such as solar and wind electricity. In addition to energy generation, the productions of valuable chemicals via electrochemical reactions are also actively pursued by scientists for a wide range of applications, including agriculture manufacturing, construction, and daily life products. The electrochemical nitrogen fixation, for example, is predicted to be effective in mild conditions, thereby minimizing energy consumption and greenhouse gas emission. The electrochemical reduction of CO₂ allows the excessive greenhouse gas to be recycled into a wide range of valuable carbon-based chemicals. Nonetheless, these envisioned applications will never be realized without proper electrocatalysts to accelerate sluggish kinetics and energy-uphill thermodynamics. Brief introductions to the related electrochemical reactions, as well as the developments and challenges of their corresponding electrocatalysts will be provided in the introduction chapter. The development of novel sustainable energy industries is highly dependent upon the research of proper, cost-efficient and durable electrocatalysts. Initially, a systematic theoretical investigation should be carried out to determine the screening criteria based on fundamental principles for the discovery of promising candidates. In contrast to the abundance of existing works employing an experimental approach, there is an insufficiency of equally supportive theoretical studies on intrinsic mechanisms. Hence, powered by DFT calculations, the research works in this thesis aim to investigate the essential microscopic mechanisms of a wide range of electrochemical reactions to propose principles for the screening and design of efficient electrocatalysts. The applications of the d-band center model and enriched discussions about it to avoid oversimplification of study were demonstrated in the works. In the meantime, this thesis also presents the attempts to theoretically interpret the experimentally outstanding electrocatalytic activity improvements of synthesized functional materials, which facilitates the studies of novel mechanisms and theory models. The attempts are centered around the high-index facets (HIFs) of transition metals and the crystal phase transformations, both of which are lacking theoretical insights to support the experimental developments of novel electrocatalysts. Consequently, the theoretical studies presented in this thesis will promote the future advancement of sustainable energy developments. |
| Rights: | All rights reserved |
| Access: | open access |
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