Nonstoichiometric rutile TiO2 photoelectrodes for improved photoelectrochemical water splitting.

A new type of nonstoichiometric rutile titanium dioxide (TiO2) film with around 15 at% oxygen vacancies homogeneously distributed throughout the bulk was prepared. The resultant films, when used as a photoelectrode, showed a photoelectrochemical water splitting activity 1.7 times that of stoichiometric TiO2 at a bias of 0.9 V vs. Ag/AgCl. This is believed to result from the synergistic effect of the improved bulk transport and surface transfer of charge carriers compared to the stoichiometric rutile TiO2.