Ce-doped SiO2@TiO2 nanocomposite as an effective visible light photocatalyst

SiO2@TiO2 nanoparticles doped with the different contents of Ce were prepared by a flow-together neutralisation process. The result of FT-IR showed that the Ti-O-Si bond was formed at the interface of the coating layer. The XRD data proved that the presence of Ce in SiO2@TiO2 could inhibit the phase transformation from anatase to rutile and enhance the thermal stability. The TEM images demonstrated that TiO2 coated with silica had smaller particle size, uniform size distribution and polished surface. The absorption spectra indicated an extension of light absorption into the visible light region for the as-prepared samples, and the electron-hole recombination could be effectively inhibited. The effects of the Ce content on the photocatalytic activity were investigated by the photodegradation of methyl orange irradiated by visible light. The results showed that the nanocomposite with 5 mol% Ce had the best ability of photo-degradation. The degradation efficiency could reach to 93.3% after reaction for 10 min, which was more efficient than that of undoped SiO2@TiO2 (47.0%). For pure P25, however, the photodegradation of MO could hardly be observed under the same condition. (C) 2013 Elsevier B. V. All rights reserved.