The effect of the hydrothermal treatment with aqueous NaOH solution on the photoelectrochemical and photocatalytic properties of visible light-responsive TiO2 thin films prepared on Ti foil substrate (Vis-TiO2/Ti) by a radio-frequency magnetron sputtering (RF-MS) deposition method has been investigated. The hydrothermally treated Vis-TiO2/Ti electrodes exhibited a significant increase in their photocurrent under UV and visible light irradiation as compared to untreated Vis-TiO2/Ti electrode. SEM investigations revealed that the surface morphology of Vis-TiO2/Ti are drastically changed from the assembly of the TiO2 crystallites to the stacking of nanowires with diameters of 30-50 nm with increasing hydrothermal treatment time (3-24 h), accompanying the increase in their surface area. The separate evolution of H-2 and 02 from water under solar light irradiation was successfully achieved using the Vis-TiO2/Ti/Pt which is hydrothermally treated for 5 h, while the H-2 evolution ratio was 15 mu mol h(-1) in the early initial stage, corresponding to a solar energy conversion efficiency of 0.23%. (C) 2008 Elsevier B.V. All rights reserved.