N,S-Codoped TiO2: Synthesis via Hydrolysis-Solvothermal Process and Visible Photocatalytic Activity

N,S-codoped TiO2 was prepared controllably by a simple phase-separated hydrolysis-solvothermal process with sulfourea as nonmetal source. The as-prepared sample has a narrowly distributed size of 10 nm and good dispersability. N,S-codoping expands the spectral response range of TiO2. The results of atmosphere-controlled surface photovoltage spectroscopy (SPS) indicate that the codoping-induced surface states could trap the holes, favoring the photogenerated charge carrier separation. The as-prepared N,S-codoped samples show higher visible photocatalytic activity for oxidizing water to O-2 and acetaldehyde degradation, even higher than that of N-doped TiO2. This is mainly attributed to the good dispersability, strong absorption for visible light and high charge carrier separation rate.