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 water‐splitting performance.