The effect of chemical etching by HF solutionon the photoelectrochemical performance and photocatalyticactivity of visible light-responsive TiO2 (Vis-TiO2)thin films prepared by a radio-frequency magnetron sputteringmethod has been investigated. It was found that Vis-TiO2 thin films treated with HF solution (HF-Vis-TiO2)exhibit a remarkable enhancement of the photoelectrochemicalperformance not only under UV but also visiblelight irradiation as compared to untreated Vis-TiO2. Theincident photon to current conversion efficiencies reached66 and 9.4% under UV (k = 360 nm) and visible light(k = 420 nm), respectively. The HF-Vis-TiO2 thin filmshave a larger surface area and higher donor density thanVis-TiO2, indicating that the remarkable increase in thephotocurrent may be due to the short diffusion length ofthe photoformed holes in reaching the solid–liquid interfaceas well as to the high conductivity. Moreover, theHF-Vis-TiO2 thin films were found to act as efficientphotocatalysts for the decomposition of water with theseparate evolution of H2 and O2 from H2O under visible orsunlight irradiation.