[Preparation and characterization of N, S, F-codoped nanosize TiO2 with ionic liquid]

N, S, F-co-doped TiO2 visible-light response photocatalyst (N-S-F-TiO2) was prepared with TiCl4, thiourea and ionic liquid (C6 mim]+ [BF4) via the microwave-catalytic hydrolysis precipitation process followed by calcination in an NH3/N2 atmosphere. It was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible diffusion reflectance spectroscopy (UV-Vis/DRS). Results showed that it was high purity anatase. The Ti-O-N, Ti-O-S and Ti-S bonds were formed in the TiO2 crystal and F used to dope TiO2 in the form of TiOF2. In the visible region 400 -550 nm, it has strong absorption, and in 600-800 nm there was a strong absorption band. N-S-F-TiO2 prepared at volume ratio of [C6 mim]+ [BF4]- /H2O of 5/95 exhibited the highest photocatalytic activity, and the degradation ratio of methyl orange was 95% under visible-light irradiation for 200 min. Multi-element co-doped synergistic effect was demonstrated by enhancement of the absorption in the visible region and higher visible light photocatalytic activity for N-S-F-TiO2.