Preparation and characterization of N–S-codoped TiO 2 photocatalyst and its photocatalytic activity

Abstract

N–S-codoped anatase nanosized TiO 2 photocatalyst (NSTO) was successfully prepared by one-step hydrothermal method from a mixed aqueous solution of Ti(SO 4) 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 TiO 2 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 TiO 2 (STO) and undoped TiO 2 (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.