AbstractAlong with the theme of global sustainable development, energy and environment are becoming the two most concerning issues in the world today. Energy conversion by photocatalysis is one of the hot topics that has received much attention. This thesis aims to explore how to efficiently utilise biomass energy via photocatalytic processes. Generally, carbohydrates, such as glucose, are the break-down products of biomass and can potentially act as energy carriers. Explorations on how to enhance photocatalytic efficiency in energy conversion processes are important. Meanwhile, highly novel microporous polymers (polymers of intrinsic microporosity, PIMs), have been proposed as effective hosts for catalysts in energy conversion applications. Such materials provide catalysts with stabilisation and protection during the electrocatalytic processes and bind gaseous reagents even in an aqueous electrolyte to introduce a gas-liquid-solid “triphasic” interfacial condition. This ability of PIMs to form a triphasic interface can significantly enhance the electrocatalytic performance, especially in the critical cases of hydrogen evolution reaction. The idea of this thesis is to explore PIMs materials as microporous hosts in photocatalysis for energy conversion from biomass, especially in the case of photocatalytic hydrogen evolution and hydrogen peroxide generation.
The thesis begins with introductory chapters, introducing the project background and aims as well as presenting reviews about materials in this study. Then, in the context of electrochemistry, fundamentals followed by electrochemical techniques employed in this thesis are introduced. The concept of photoelectrochemical systems and photoelectrochemical measurements are demonstrated in this part. In chapter 3, a novel photoelectrochemical system based on photocatalyst Pt@g-C3N4 were initially designed and studied. A modified photoelectrode with photocatalyst was prepared and investigated for the critical case of hydrogen evolution close to a platinum electrode. Hydrogen is generated as an energy carrier via photocatalysis in the presence of a glucose quencher. Chapter 4 presents an indirect sensing device based on the previously tested photoelectrochemical system. This work investigates photoresponses with a wider range of carbohydrates during the photocatalytic process, opening the door to effective biomass energy conversion. Chapter 5 further investigates photoelectrochemical signals derived from photogenerated hydrogen product with a robust Clark-type probe. Size selectivity and photocurrent enhancing effects from the microporous hosts are revealed. In chapter 6, heterogenisation of g-C3N4 photocatalysts into microporous polymers is demonstrated for enhanced photocatalytical hydrogen peroxide production. Overall, hydrogen and hydrogen peroxide with high chemical values can be effectively generated by photocatalysis in the presence of carbohydrate quenchers. The important role of microporous hosts for enhanced photocatalytic reactions has been observed.
|Date of Award||22 Jun 2022|
|Supervisor||Frank Marken (Supervisor) & Karen Edler (Supervisor)|
- Hydrogen evolution
- Biomass conversion