Photo-oxidation of water sensitized by WO3 powder

Abstract

WO₃ powder photosensitized the oxidation of water by Fe³⁺ ions with blue light (400–450 nm). The formal quantum efficiency for oxygen production at 405 nm was (3.1 ± 0.1)× 10^–3 mol ein^–1. Oxygen production was partially inhibited by Fe²⁺, oxygen and high concentrations of Fe³⁺(> 10^–2 mol dm^–3). Depositing RuO₂ on to the semiconductor powder produced a moderate increase in the rate of oxygen production, while deposits of Pt, Rh and Ru lead to a decrease in the rate of oxygen formation. Unlike most of the artificial systems which have been described for the photo-oxidation of water with visible light, this system operates with an electron acceptor (Fe³⁺) which is part of a reversible redox couple (Fe³⁺/Fe²⁺).