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

Abstract TiO 2 /SiO 2 /Bi 2 O 3 photocatalysts were prepared from TiOSO 4 , SiO 2 sol and Bi(NO 3 ) 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 Bi 2 O 3 , only anatase-TiO 2 was observed, and no diffraction peaks of SiO 2 and Bi 2 O 3 came up in XRD pattern. The surface areas of TiO 2 /SiO 2 and TiO 2 /SiO 2 /Bi 2 O 3 were obviously larger than that of pure TiO 2 . The addition of Bi 2 O 3 improved the absorption of the TiO 2 /SiO 2 /Bi 2 O 3 samples under ultraviolet and visible light. The hydroxyl peak areas of the TiO 2 /SiO 2 , TiO 2 /Bi 2 O 3 and TiO 2 /SiO 2 /Bi 2 O 3 were higher than those of pure TiO 2 and Bi 2 O 3 . The TiO 2 /Bi 2 O 3 heterojunction structure enhanced separation of photogenerated electrons and holes under UV and visible light. The TiO 2 /SiO 2 /Bi 2 O 3 containing 2.5% of Bi 2 O 3 has the highest activity in all of the samples under UV or visible irradiation.