Effect of co-doping and tri-doping with transition metals and a nonmetal on photocatalytic activity in visible light of TiO2 thin film

Mono, co- and tri-doped TiO 2 thin films with the transition metals (vanadium and/or chrominium) and a nonmetal (nitrogen) have been fabricated by sol-gel method. X-ray diffraction results clearly reveal anatase crystal structure for all obtained samples and doping with any dopants doesn’t change the anatase phase of TiO 2 . Compared to TiO 2 , three types of doped TiO 2 thin films exhibit a red-shift in the absorption edge and have much better photocatalytic properties for methylene blue degradation in visible light region. The maximum visible-photocatalytic performance was achieved for tri-doped TiO 2 sample. The mechanism for enhancing visible-photocatalytic activity of co-doped and tri-doped TiO 2 thin films was also examined.