H2 Production from Catalytic Photoreforming of Cellulose Using TiO2-based Catalyst

Abstract

Energy dilemma along with environmental issues (i.e. global warming by carbon emissions) derived from the ever increasing energy consumption, which relies on unsustainable resources, are among the greatest challenges faced by our society. To tackle the energy crisis worldwide, research should focus on the development of sustainable approaches for producing clean energy to reduce the intensive use of fossil resources. Here, this thesis focuses on the investigation of photoreforming of cellulose (over TiO2-based catalysts) for hydrogen (H2) production, which is one of the strategies for clean and sustainable hydrogen energy. In this PhD research, the reaction conditions and mechanism of cellulose photoreforming for H2 production, as well as the development of the photoreforming catalysts and cellulose pre-treatment methods, have been investigated. The systematic study of this reaction system revealed an optimum operating condition (at 40 °C with 1.0 g L−1 of cellulose and 0.75 g L−1 over 0.16% Pt/m-TiO2 catalyst) which delivered a H2 production rate at 9.95 µmol h−1. Also, a mechanistic study on the system was conducted, and the results showed that H2 was produced mainly via the reduction of the protons in water through a formic acid-driven route. The insight gained into the photoreforming system then motivated the research into the correlation between the photoreforming catalysts (i.e. Pt/TiO2 catalysts) and their activity. Under the optimum operating condition, based on the analysis of the normalised H2 production rate (with respect to the specific area and actual Pt loading), small Pt particles (at sub-nanometre) are highly beneficial to improve H2 production. Additionally, the effect of the pre-treatments (i.e. ball-milling, BM, and plasma) of cellulose on H2 production from the photoreforming system was also investigated. The BM pre-treatment was found relatively effective to disrupt the cellulose structure, and the associated recrystallisation in water and reduced polymerisation degree of the BM-treated cellulose was beneficial to H2 production in aqueous photoreforming reactions.

Date of Award	23 Nov 2021
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Xiaolei Fan (Supervisor) & Chris Hardacre (Supervisor)