Photocatalytic activity of metal-doped titanium oxide films prepared by sol-gel process

Abstract

Visible-light photocatalytic activity of metal-doped TiO2 films prepared by dipcoating method was investigated. Cu, Fe, and Al atoms were doped in the TiO2 films and they exist as their oxide in the nearly stoichiometric TiO2 matrices. It is found that the Cu doping is effective for visible-light photocatalysis of the TiO2 films, while Fe- and Al-doped films hardly shows visible-light photocatalytic activity. The optical absorption spectra for the non-doped and metal-doped TiO2 films show that effective band gap narrowing is observed in the Fe- and Cu-doped TiO2 films. Recombination of the photogenerated electron/hole pairs takes place quickly in the Fe-doped TiO2 film, while the charge separation of the photogenerated electron/hole pairs takes place effectively in the Cu-doped TiO2 film. Al doping into the TiO2 film has hardly effect on photocatalysis of TiO2 films. © 2007 IOP Publishing Ltd.