Photosensitised dissociation of water using dispersed suspensions of n-type semiconductors
Abstract
n-Type semiconductor powders (TiO2 and SrTiO3) were used to sensitise the photochemical cleavage of water using u.v. light (λ < 400 nm) under conditions of room temperature and pressure. Although several methods of platinising these powders were used, one method in particular (involving precipitation of a platinum sol, by addition of an inert electrolyte, in the presence of the semiconductor powder) was found to produce an efficient photocatalyst for water reduction. Many different photocatalysts were tested for water reduction activity, using EDTA as an electron donor, and for water oxidation activity, using Fe3+ as an electron acceptor. In the absence of EDTA and Fe3+, u.v. irradiation of these photocatalysts liberated H2 but O2 evolution was not observed. Reasons for these observations are discussed.