Multi-electron storage of photoenergy using Cu2O–TiO2 thin film photocatalyst

UV–vis irradiation of thin films of TiO2 (ITO/TiO2) and Cu2O/TiO2 (ITO/Cu2O/TiO2) coated on conducting glasses generate H2 from H2O and once the illumination is ceased, the H2 production was still noticeable under dark for ITO/Cu2O/TiO2 at a lesser production rate for up to 2 h. No such dark reactions were observed for ITO/TiO2 or TiO2-coated copper metal foil (Cu/TiO2). It was noticed that the irradiation of ITO/Cu2O/TiO2 leads to formation of trapped electrons and this stored energy leads to generate H2 from H2O in the dark.