University of Twente Student Theses


Photoelectrochemical Water Splitting Using Metal Oxides

Kishore, R. (2016) Photoelectrochemical Water Splitting Using Metal Oxides.

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Abstract:Solar fuel conversion is one of our long term strategies to achieve clean energy and environmental sustainability. We use Tungsten Oxide (WO3) and Bismuth Vanadate (BiVO4) as photoelectrode material in photoelectrochemical (PEC) water splitting. Our aim is to identify the rate limiting step in the PEC process and to improve its efficiency. Density functional theory calculations (DFT) are performed to study the oxygen evolution reaction (OER) on the metal oxide surface. The free energies of the proton coupled electron transfer steps are calculated. The effects of surface orientation, doping and oxygen vacancies in the surface are also analysed. Identification of good dopants, active sites and surface orientations in this manner could save a lot of experimental effort directed at tailoring of the metal oxide surface to make the reaction more efficient. For WO3, the (200) surface was found to be most photo active surface and Mo doping proved effective in reducing the rate limiting over-potential for this surface. It was also concluded that presence of oxygen vacancies may help to decrease or increase the overpotential of the rate limiting step depending upon its position in the WO3 geometry. For BiVO4, the V site was identified as the most active site for water splitting. Introducing dopants on V site was found to be more effective than Bi site. Also Phosphorous was identified as a good dopant for the same. It was also concluded that the reaction was likely to occur on another V site in case of P doping.
Item Type:Internship Report (Master)
Dutch Institute for Fundamental Energy Research, the Netherlands
Faculty:ET: Engineering Technology
Subject:52 mechanical engineering
Programme:Sustainable Energy Technology MSc (60443)
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