Mechanism of photocatalytic decomposition of water into H2 and O2 over NiO$z.sbnd;SrTiO3

The mechanism of the photocatalytic decomposition of H2O into H2 and O2 over NiOSrTiO3 powder was studied on the basis of the structure of the catalyst. It was elucidated that H2 evolution occurs over NiO while O2 evolution takes place over SrTiO3. The importance of the existence of Ni metal between the interface of NiO and SrTiO3 suggested the transfer of an electron between both materials. Two possible mechanisms, a one-photon process and a two-photon process, were discussed.