Two-step water splitting system using two different semiconductor photocatalysts and a shuttle redox mediator IO_3~-/I~-

摘要

A new photocatalytic reaction that splits water into H_2 and O_2 was designed by a two-step photoexcitation system composed of a IO_3~-/I~- redox mediator and two different semiconductor photocatalysts. It was found that water oxidation into O_2 in the presence of IO_3~- electron acceptor efficiently took place over TiO_2-rutile and WO_3 photocatalysts, which were used as an O_2 production photocatalyst. TiO_2-anatase and SrTiO_3 (doped with Cr, Ta) showed activity for H_2 production from aqueous solution containing I~- as an electron donor, and were used as a H_2 production photocatalyst.