Titanium dioxide (TiO2) photocatalytic films can be excited only by UV light which is about 4-5% of the overall solar spectrum and the activity under visible light irradiation is very limited. In this study, atomic layer deposition was used to deposit ZrO2-doped TiO2 films which had better visible light response. X-ray diffraction, electron microscopy and Raman, X-ray photoelectron, and UV-visible spectroscopy were used to characterize the films. The photocatalytic activities were measured by decomposition of stearic acid coating. ZrO2-doped TiO2 retained the anatase crystal phase when zirconium substitution was below 10%. The doped film with 9:1 Ti:Zr pulse ratio has greater visible light absorption and a bandgap reduction of 0.2 eV. The photocatalytic decomposition efficiency under visible light irradiation was increased by 50% compared to undoped TiO2. (c) 2007 The Electrochemical Study.