Degradation of benzene on TiO2/SiO2/Bi2O3 photocatalysts under UV and visible light

TiO2/SiO2/Bi2O3 photocatalysts were prepared from TiOSO4, SiO2 sol and Bi(NO3)(3) by the co-precipitation method and were characterized by X-ray diffraction (XRD), N-2 adsorption/desorption (BET), UV vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy (PLS) and fourier transform infrared spectroscopy (FT-IR) techniques. In the as-prepared samples, except for pure Bi2O3, only anatase-TiO2 was observed, and no diffraction peaks of SiO2 and Bi2O3 came up in XRD pattern. The surface areas of TiO2/SiO2 and TiO2/SiO2/Bi2O3 were obviously larger than that of pure TiO2. The addition of Bi2O3 improved the absorption of the TiO2/SiO2/Bi2O3 samples under ultraviolet and visible light. The hydroxyl peak areas of the TiO2/SiO2, TiO2/Bi2O3 and TiO2/SiO2/Bi2O3 were higher than those of pure TiO2 and Bi2O3. The TiO2/Bi2O3 heterojunction structure enhanced separation of photogenerated electrons and holes under UV and visible light. The TiO2/SiO2/Bi2O3 containing 2.5% of Bi2O3 has the highest activity in all of the samples under UV or visible irradiation. (C) 2014 Elsevier B.V. All rights reserved.