Photoelectrocatalytic Water Splitting

Contacts:

Billie Abrams, Department of Physics, CINF-DTU, 4525-3113 (billie.abrams@fysik.dtu.dk)

Peter Vesborg, Department of Physics, CINF-DTU, 4525-3113 (vesborg@fysik.dtu.dk)

Official supervisor: Ib Chorkendorff, Department of Physics, CINF-DTU, 4525-3170 (ibchork@fysik.dtu.dk)

Photoelectrocatalytic water splitting schematic showing two electrodes participating in the reaction (left). The ideal would be to find a photocatalyst that works using visible light as shown in the solar spectrum on the right.

Hydrogen is one of the candidates to replace oil as a future energy carrier. Photoelectrocatalytic splitting of water is one way to produce clean hydrogen. By shining light on a semiconductor photoelectrode, electrons participate in the reduction of hydrogen ions to hydrogen gas, and holes oxidize water to oxygen (and hydrogen ions). One of the main barriers in photocatalytic hydrogen production is finding a material that meets all the requirements: correct band gap (energetics), corrosion stable, good charge transport, cheap and active. The most utilized material is TiO2 but it has the drawback of having a large bandgap (3.0-3.2eV) requiring UV light excitation. Ideally we would like to find a material that is photocatalytically active in the visible region of the solar spectrum.

This project involves the photocharacterization of new potential materials for the photoelectrocatalytic water splitting process and comparing them to standard forms of TiO2. The photocharacterization includes photoactivity for water splitting, determination of the bandgap and the position of the conduction and valence bands. You will then correlate these characteristics with the redox potential for the water splitting reactions and determine efficiencies.