Preparation and characterization of N-S-codoped TiO2 photocatalyst and its photocatalytic activity

N-S-codoped anatase nanosized TiO2 photocatalyst (NSTO) was successfully prepared by one-step hydrothermal method from a mixed aqueous solution of Ti(SO4)2 and thiourea. The samples were characterized by XRD, UV-vis, XPS, FT-IR and EA. From results of UV-vis, a red shift of the absorption edge was brought out owing to N and S codoping, and the extension for photoabsorption range of NSTO occurred. XRD, XPS, EA and FT-IR studies revealed that N and S were in situ codoped in the lattice of TiO2 and N concentration decreased from the surface to the center of NSTO. Especially, the photocatalytic tests indicated that NSTO exhibited a high activity for decompositions of methyl orange both under UV-light and vis-light irradiation comparing to S-doped TiO2 (STO) and undoped TiO2 (TO). The high activity of NSTO can be related to the results of the synergetic effects of strong absorption in the UV-vis region, red shift in adsorption edge, oxygen vacancies and the enhancement of surface acidity induced by N and S codoping.