Preparation of S-doped TiO₂ photocatalysts and their photocatalytic activities under visible light

Although titanium dioxide photocatalysts having anatase phase are a promising substrate for photodegradation of pollutants in water and air, their photocatalytic activities show only under ultraviolet (UV) light. For us to utilized a wide range of incident light such as solar light, development of the photocatalysts whose activities show under visible light is one of the most important strategies. We have synthesized chemically modified titanium dioxide photocatalysts in which S (S⁴⁺) substitutes for some of the lattice titanium atoms. They show strong absorption for visible light and high activities for degradation of methylene blue, 2-propanol in aqueous solution and partial oxidation of adamantane under irradiation at wavelengths longer than 440nm. The oxidation state of the S atoms incorporated into the TiO₂ particles is determined to be mainly S⁴⁺ from X-ray photoelectron spectra (XPS) spectra.