Effects of V and Zn codoping on the microstructures and photocatalytic activities of nanocrystalline TiO2 films

To enhance the photocatalytic activity of TiO2, V and Zn co-doped TiO2 films were synthesized by the sol–gel method. The experimental results indicated that the films were composed of round-like nano-particles or aggregates. V and Zn codoping could not only obviously increase the specific surface area of TiO2 but also result in the narrowed band gap of TiO2 sample. The photocatalytic activities of the TiO2 films were evaluated by the photocatalytic decomposition of organic dyes in aqueous solution. Compared with un-doped TiO2 film or single doped TiO2 film, V and Zn co-doped TiO2 film exhibited excellent photocatalytic activities under both UV light and visible light. The improvement mechanism by V and Zn codoping was also discussed.