2016 Volume 24 Pages 92-97
TiO2 is a well-known semiconductor photocatalyst, but the wide band-gap restricts its application to solar energy conversion. We demonstrated that tantalum and nitrogen-codoped rutile TiO2 was an active photocatalyst for water oxidation under visible light. It achieved overall water splitting in combination with a H2-evolution photocatalyst of SrTiO3:Rh and an Fe3+/Fe2+ redox couple even under simulated sunlight. We also found that rutile TiO2 modified with cobalt hydroxide nanoclusters was capable of harvesting visible light with wavelengths of up to 850 nm, and photocatalyzing water oxidation to produce molecular O2. To our knowledge, this system provides the first demonstration of a photocatalytic material capable of water oxidation upon excitation by visible light up to such a long wavelength, even with the use of earth-abundant elements only.