Photoelectrochemical properties of hybrid WO3/TiO2 electrode. Effect of structures of WO3 on charge separation behavior

In this study, morphology, structure, fundamental absorption edge and photocurrent response of hybrid WO3/TiO2 films were investigated. It was found that the band gap excitation of WO3/TiO2 caused effective charge separation to generate high anodic photocurrent by the oxidation of oxalic acid, and, in particular, a WO3/TiO2 electrode having an amorphous-like WO3 phase exhibited higher photocurrent than either WO3 or TiO2 itself. We demonstrated differences of two types of composite films between amorphous-like WO3 and polycrystalline WO3 supported on TiO2 using energy band structures.