Transparent TiO2 films on stainless steel prepared by dip coating in a nonionic microemulsions solution have been shown to have much higher photocatalytic activity than those coatings on glass. Fe3+ and Fe2+ ions, diffusing from stainless steel substrate into TiO2 films during high-temperature calcination, behave as dopants to significantly affect the films' photocatalytic activity. An optimum calcination condition, under which the amount of diffused Fe3+ and the ratio of Fe3+ to Fe2+ ions favor the film's photocatalytic reaction, was obtained. In addition, this TiO2 films also exhibits excellent photoinduced hydrophilicity and antibacterial effect for the sterilization of Bacillus pumilus. As stainless steel is a very common material, practical systems for pollution treatment and disinfection may be designed based on this enhanced coating. Copyright © 2003 American Chemical Society.