Designing and Preparing a Thin-Film Photocatalyst from Titanium Dioxide Nanotubes Codoped with Nitrogen and Fluorine

Thin-film nanostructured coatings have been produced electrolytically from TiO2 codoped with nitrogen and fluorine. The resulting films consist of individual TiO2 nanotubes with the polycrystalline anatase structure; they are characterized by narrow size distribution and a high degree of local self-organization. Diffuse reflectance spectroscopy demonstrates that the absorption edge of the samples codoped with nitrogen and fluorine is shifted towards the longer wavelength region of the solar spectrum by 200 nm with respect to pure TiO2. When irradiated with visible light, the synthesized TiO2 films exhibit high photocatalytic activity in the reaction of phenol oxidation in aqueous media.