Hydrogen and Oxygen Evolution Photocatalysts Synthesized from Strontium Titanate by Controlled Doping and Their Performance in Two-Step Overall Water Splitting under Visible Light

A visible-light-induced two-step overall water splitting was achieved by combining two types of photocatalysts prepared by introducing foreign elements into the identical mother structure with a controlled electronic band structure. Strontium titanate (SrTiO3) was selected as the mother structure and was doped with either vanadium (and sodium) or rhodium to introduce visible light sensitivity. By utilizing these two types of SrTiO3-based photocatalysts, simultaneous liberation of hydrogen (H-2) and oxygen (O-2) with a molar ratio of similar to 2:1 was achieved in the presence of iodate ion (IO3-)/iodide ion (I-) as a redox mediator under irradiation with only visible light (> 420 nm).