Preparation and Photocatalytic Activity of Cu-doped BiVO<SUB>4</SUB> Photocatalysts Fabricated by Hydrothermal Method

Abstract

Cu-BiVO4 photocatalysts were prepared by hydrothermal method using Bi(NO3)3·5H2O, NH4VO3 and Cu(NO3)2·3H2O as raw materials. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscope (XPS) and UV-Vis diffusion reflectance spectra (UV-Vis). The results show that highly crystalline monoclinic scheelite structure of Cu-BiVO4 is obtained by increasing the pH value, and the crystal structures of BiVO4 are no change with the increasing of Cu dopant. XPS results reveal that the doped Cu species exists in the form of CuO and Cu2O. The Cu-BiVO4 catalyst has a significant red-shift in the absorption band in the visible region, and the absorption intensity increases greatly for the composite catalyst compared with pure BiVO4. The Cu-BiVO4 photocatalysts enhance the photocatalytic activities for degradation of methylene blue (MB) under visible light irradiation. When pH value is 5.0 and Cu dopant is 1.0wt%, the photo- catalytic activities reach the maximum. After visible light irradiation for 60 min, the removal rate of MB by Cu-BiVO4(1.0wt% Cu) at 10 mg/L initial concentration increases to 97.8% while the removal rate of MB by pure BiVO4 is only 54.7%. The mechanism of enhanced photocatalytic activity is also discussed.