Photocatalytic activities of Ce or Co doped nanocrystalline TiO2–SiO2 composite films

Ce or Co doped nanocrystalline TiO2–SiO2 composite films were prepared by the sol–gel method. The high-resolution field emission scanning electron microscopy (FE-SEM) results indicated the films to be composed of round-like nano-particles or aggregates 4–10 nm in size. Compared with transition metal Co doped TiO2–SiO2 film, the surface of lanthanide metal Ce doped TiO2–SiO2 film was more uniform and smooth with smaller particles and larger specific surface area. The photocatalytic activities of the films were evaluated by degradation of an organic dye in solution. Ce doped TiO2–SiO2 film exhibited excellent photocatalytic activity compared to Co doped TiO2–SiO2 film. It is believed that the surface microstructure of the modified film and the special electronic structure of dopant Ce are responsible for improving the photocatalytic activity.