Synthesis and visible light photo-electrochemical behaviors of In2O3-sensitized ZnO nanowire array film

In2O3-sensitized ZnO nanowire (NW) array film with improving visible light activity was synthesized on F-doped SnO2 (FTO) glass substrate by a facile two-step process. The films, ZnO NW arrays and In2O3-sensitized ZnO NW arrays, were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV–vis diffuse reflectance spectroscopy. For the films severed as the photoanodes in a three-electrode system, the photo-electrochemical behaviors were investigated and the photocatalytic activity was evaluated by the oxidation of glucose under visible light irradiation. The results show that the ZnO NW arrays are highly ZnO (0 0 2) orientated with a diameter of 100 nm and a length of 3 μm, and In2O3 nanoparticles grow and form a shell film on the wall of the ZnO NW array in the In2O3-sensitized ZnO NW array film. This composite structure shows a red shift from ultraviolet (λ = 385 nm) to the visible-light region (λ = 450 nm) in the maximum optical response. The incorporation of In2O3 into the ZnO NW array film remarkably promotes the photogenerated carrier separation and increases the utilization of photogenerated carriers in photocatalytic reactions, resulting in the higher photocatalytic activity under visible light.