Development of new photocatalytic water splitting into H2 and O2 using two different semiconductor photocatalysts and a shuttle redox mediator IO3(super -)/I(super -)

A new type of photocatalytic reaction that splits water into H2 and O2 is designed using a two-step photoexcitation system composed of an iodate/iodide [IO3(super -)/I(super -)] shuttle redox mediator and two different photocatalysts, one for H2 evolution and the other for O2 evolution. Photocatalytic oxidation of water to O2 and reduction of IO3(super -) to I(super -) selectively proceeded with good efficiencies over TiO2-rutile and Pt-WO3 photocatalysts under UV and visible light irradiations.