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Title: Photoelectrochemical water splitting for hydrogen production using III-V semiconductor materials
Author: Alqahtani, Mahdi Mohammed
ISNI:       0000 0004 7970 7120
Awarding Body: UCL (University College London)
Current Institution: University College London (University of London)
Date of Award: 2019
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The use of photoelectrochemical (PEC) water splitting to harvest intermittent solar sources in the form of hydrogen is an attractive potential method to address energy and environmental issues. Since 1972, when Honda and Fujishima demonstrated the use of titanium dioxide (TiO2) in PEC water splitting (1), extensive efforts have been devoted to the development of photoelectrode stability and high solar-to-hydrogen efficiency. Metal oxides (e.g. TiO2, Fe2O3, BiVO4, and SrTiO2) have been extensively studied but their large band gap and sluggish charge transfer kinetics typically limited their solar-to-hydrogen conversion efficiency (1-9). III-V semiconductor materials have proven attractive for PEC water splitting due to their high efficiency, optimal band gap, and excellent optical properties but they are readily susceptible to corrosion in strongly acidic or basic aqueous solutions during the PEC process (10-18). This thesis aims to construct a PEC device (e.g. photoanode and photocathode) based on III-V semiconductor materials (such as InGaN, GaP, and GaPSb) for PEC water splitting. The design of a direct PEC water splitting device requires a suitable band gap to cover the entire solar spectrum (visible range), which leads to a high photocurrent and solar-to-hydrogen (STH) efficiency. The band edge alignment must straddle the hydrogen and oxygen redox potentials and stable under illumination in electrolyte conditions (19). However, the current challenge is to develop efficient and stable solar-to-chemical conversion systems based on III-V semiconductor materials for PEC water splitting. This can be addressed by incorporating novel co-catalysts that are physically and electrically attached to the surface of the photoelectrodes. The role of the co-catalyst is to minimize the overpotentials and accelerate the charge kinetics at the semiconductor/electrolyte interface (20). Additionally, the surface modification strategy of applying co-catalysts can extend the stability of the photoelectrode for long-time operation (21-25).
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available