TiO2 and WO3 semiconductor particles in contact: photochemical reduction of WO3 to the non-stoichiometric blue form
Hydrated tungsten oxide WO3.xH2O in contact with TiO2 grains suspended in water is found to reduce to WO2.96.xH2O upon irradiation with UV light. Measurement of the band position of WO3.xH2O suggests that electron transfer from TiO2 to WO3.xH2O is responsible for the reduction.