Nanocrystalline TiO2 composte films for enhanced photocatalytic activity

In order to extend light response of TiO2 into the visible region and enhance its photocatalytic activity, V and W surface codoped nanocrytalline TiO2 film was synthesized by the sol-gel method. Tetrabutyl titanate (Ti(OC4H9)(4)) was chosen as the precursor, and ammonium metavanadate or ammonium tungstate was chosen as vanadium or tungsten source. The high-resolution field emission scanning electron microscopy (FE-SEM) results revealed that the film was composed of uniform round-like nano-particles with size smaller than 6 nm. The photocatalytic activities of TiO2 films were investigated by degradation of organic dyes in aqueous solutions. V and W codoped TiO2 film exhibited excellent photocatalytic activity compared to undoped TiO2 film or single doped TiO2 film. The improvement mechanism by V and W codoping was also discussed.