Graphene-titania hybrid photoanodes by supersonic kinetic spraying for solar water splitting

We report the synthesis of graphene-TiO₂ (G-TiO₂) composite films that exhibit significantly enhanced photoelectrochemical water-splitting performance relative to pure TiO₂. Supersonic kinetic spraying was used to produce strongly adhered, electrically and mechanically robust G-TiO₂ composite films containing 0.1, 0.5, 1.0, and 5.0 wt.% graphene. Films with an intermediate graphene content of 1.0 wt.% demonstrated the best water-splitting performance. G-TiO₂ composite films with 1.0 wt.% graphene exhibited photocurrent density ten times that of pure TiO₂ films. The electron transfer between TiO₂ and graphene suppresses the recombination of photoinduced charge carriers and prolongs the electron excited-state lifetime, which contributes to the enhanced photoelectrochemical watersplitting performance.