Wang, Qiming;
(2023)
Design, Deactivation and Deployment of Functional Materials in Green Chemical Conversion.
Doctoral thesis (Ph.D), UCL (University College London).
Abstract
The rapid development of society has greatly improved living standards and global economic power. However, it has also led to a range of environmental problems. Issues such as the depletion of fossil fuels and the accumulation of waste plastics have had detrimental effects on global temperature and ocean acidity. To address these global environmental challenges, it has become essential to explore alternative carbon sources and develop new environmentally-friendly chemical conversion processes. This thesis focuses on the untapped potential of agricultural biomass, carbon dioxide (CO2), and plastic waste for future refinery technologies. These resources have not been fully utilized, but they hold significant promise. Agricultural biomass can be converted into biofuels, offering a renewable and sustainable alternative to fossil fuels. CO2 can be captured and effectively utilized in diverse industries, such as chemical production, fuel synthesis, and building material development. Plastic waste can be recycled and transformed into new products, reducing environmental pollution and conserving valuable resources. By investing in the right technologies and approaches, these energy and material sources have the potential to reduce our reliance on finite resources and mitigate environmental impact. Furthermore, this thesis delves into the design, deployment, and deactivation of advanced materials in green chemical conversion and heterogeneous catalysis. It explores the fundamental concepts underlying sustainable and green chemistry principles. The importance of material function in relation to the conversion processes is discussed, highlighting the ability to modulate material composition and surface structure to enhance productivity and ensure long-term stability. The first project focuses on achieving excellent catalytic performance in the selective transformation of biomass platform chemical 5-hydroxymethylfurfural (5-HMF). The development of a polyphenylene (PPhen) framework incorporated with Ru nanoparticles (Ru/PPhen) is achieved through a swelling-impregnation method. This catalyst effectively converts 5-HMF into the biofuel 2,5-dimethylfuran (2,5-DMF) under mild conditions. The approach isolates 5-HMF through the π-π stacking effect and selectively cleaves the C-OH bond while minimizing byproduct formation. This innovative strategy enhances biomass conversions and catalysis. The second project proposes a novel metathesis reaction that involves the interaction between metal oxides and fluorocarbon. Building on previous research that utilized Teflon in silica synthesis,1 this reaction is referred to as fluoro-oxygen metathesis. It involves the breaking of C-F and M-O bonds, while simultaneously forming C-O and M-F bonds. This unique transformation provides a general mechanism for the production of halogen-containing inorganic salts, utilizing waste polytetrafluoroethylene (PTFE) as a starting material. This research aims to make waste polymers more environmentally friendly through recycling processes or the development of biodegradable polymers. Despite advancements, understanding the deactivation process of industrial catalysts continues to pose challenges. One such catalyst system widely employed in industry since 1960 is Cu/ZnO/Al2O3 for methanol synthesis from syngas (a mixture of CO2, H2, and CO). This thesis addresses the limitations imposed by the "length scale gap" by combining catalytic performance evaluations with spatiotemporal nanoscale characterization techniques. Specifically, the 6D Identical imaging method is employed to track the physicochemical structural/performance relationship at multiple length scales while simultaneously probing the behavior of Cu and Zn at identical locations. Overall, this thesis addresses the requirement for sustainable and environmentally friendly chemical conversions, explores the untapped potential of various resources, and investigates the design, deployment, and deactivation of advanced materials in green chemical conversion.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Design, Deactivation and Deployment of Functional Materials in Green Chemical Conversion |
| Language: | English |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Chemical Engineering |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10182782 |
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