Chen, Sining;
(2025)
Structure-activity relationship research on supported Ni catalysts in CO2 methanation.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
The Sabatier reaction (CO2 methanation) represents a facile catalytic process to produce CH4 at relatively low temperatures and with high yields. Ni supported on ceria (Ni/CeO2) is widely recognised as an active catalyst due to the enriched Ni–CeOx interfacial sites. Here, the physicochemical properties of Ni/CeO2 are investigated by a variety of characterisation methods, including but not limited to X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), and kerr-gated Raman to establish structure-activity relationships for CO2 methanation. In Chapter 3, the critical role of Ni availability, affected by both Ni particle size and potential encapsulation by reduced CeOx due to a strong metal-support interaction (SMSI), in forming interfacial sites, is highlighted. Chapter 4 examines the positive role of the surface oxygen vacancies (Ov) which was found to enhance Ni availability and MSI in Ni/CeO2 catalysts by creating a disordered and defective ceria film at the interface. This defect-dense Ni–CeOx interface altered the bonding mode between bidentate carbonates during the reaction. Results in chapter 5 evidenced the presence of Ni encapsulation, and confirmed the catalyst stability under at different activation temperatures and operating conditions. In Chapter 6, a two-dimensional (2D) Ni/CeO2 with single Ni NPs on CeO2 (100) crystal was explored using quasi in situ X-ray photoemission electron microscope (X-PEEM) and soft XAS. Detailed spatial analysis of Ni NPs and the surrounding Ce environment proposed the positive role of MSI for Ni reducibility and potential tuning methods. Also, the potential reconfigurations of Ni/CeO2 (e.g. oxidation/reduction and sintering/redispersion), were revealed under CO2 hydrogenation. In summary, the comprehensive research allowed us to better understand the role of Ov, Ni size and MSI in the formation of interfacial sites, and the correlation among these properties, essential for future designs of promising supported Ni catalysts for CO2 hydrogenation.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Structure-activity relationship research on supported Ni catalysts in CO2 methanation |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2025. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Chemistry |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10206098 |
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