Photocatalytic oxidation of various compounds over TiO₂ and other semiconductor oxides; Mechanistic considerations

Abstract

Abstract A synthesis of studies on the photocatalytic oxidation of various compounds (isobutane, propene, alkyltoluenes, butanols, ammonia, halide ions in aqueous solution) is presented, TiO 2 being the main photocatalyst. Comparisons are also made with other n‐type semiconductors: ZrO 2 , V 2 O 5 , Sb 2 O 4 , ZnO, SnO 2 , CeO 2 , WO 3 . Information about the mechanism has been obtained by (i) an examination of the photocatalytic isotopic exchange of oxygen in competition with the oxidation of a hydrocarbon, (ii) kinetics and photoconductivity measurements, and (iii) oxidation of butanols by NO. The main conclusions are that these reactions proceed in an adsorbed phase and that dissociated oxygen species play an essential role.