Sulfur-doped anatase TiO2 nanoparticles with sulfur atoms occupying oxygen sites were realized by low temperature hydrothermal oxidation of titanium disulfide (TiS2) with deionized water as the solvent. S doping can effectively narrow the bandgap of TiO2 due to the fact that S 3p level is higher than O 2p orbital. The large surface area caused by this doping method induces higher photocatalytic activity in the visible regime compared with S-TiO2 oxidized at high temperature. The low-temperature hydrothermal oxidation of TiS2 in pH neutral solvent is an environmental-friendly method to obtain S-TiO2 with high photocatalytic activity, which can be extended to other nonmetal doping of TiO2 or other semiconductors for bandgap engineering. (C) 2016 Elsevier Ltd. All rights reserved.