Undoped and Mo(VI) ions doped TiO2 thin films were prepared via sol-gel method on different substrates. The morphology and the crystalline structures of the thin films were studied by SEM and XRD. The UV light inducing hydrophilicity was improved by doping Mo(VI) ions. The influence of the dopant density on the photo-induced superhydrophilicity of the films was investigated using cyclic voltammetry. A new oxidation peak was observed at about 0.17 V when the TiO2 electrodes were irradiated by UV light for a certain time. The peak current increased with the irradiation time. To reach the same peak current, 0.75% Mo(VI) ions doped films required short time than the undoped film. (c) 2007 Elsevier B.V. All rights reserved.