Photocatalysts for water splitting developed by the present authors are reviewed. A NiO (0.2 wt%)/NaTaO 3:La (2%) photocatalyst with a 4.1-eV band gap showed high activity for water splitting into H 2 and O 2 with an apparent quantum yield of 56% at 270 nm. Many visible-light-driven photocatalysts have also been developed through band engineering by doping of metal cations, forming new valence bands with Bi 6S, Sn 5S, and Ag 4d orbitals, and by making solid solutions between ZnS with wide band gap and narrow band gap semiconductors. Overall water splitting under visible light irradiation has been achieved by construction of a Z-scheme photocatalysis system employing the visible-light-driven photocatalysts for H 2 and O 2 evolution, and the Fe 3+/Fe 2+ redox couple as an electron relay.
ASJC Scopus subject areas