Enhancement of the visible light photocatalytic activity of vanadium and nitrogen co-doped TiO2 thin film

Vanadium and nitrogen co-doped TiO2(TiO2:(V, N)) thin films were fabricated by sol-gel method. Crystal structure, surface morphology, chemical composition and absorption edge of the thin films were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and UV-Vis spectroscopy techniques, respectively. Photocatalytic activity of all thin films were evaluated by measuring decomposition rate of methylene blue solution under visible light irradiation. The water contact angle analyzer was used to measure water contact angle on the film. The results indicate that absorption edge of TiO2:(V, N) thin films shifts to visible region. All co-doped TiO2 samples show higher visible light photocatalytic activity than undoped TiO2 and single-element-doped TiO2 counterparts. The best TiO2:(V, N) thin film can decompose about 90% MB solution and gets super wet state after 150 min under compact light irradiation.