The Preparation And Performance Study Of Visible-Light-Responsive Bismuth-base Photocatalysts

BiVO₄has a narrow band gap of2.4eV, nontoxic. Owing to its strong ability to catalytic decompose water and organics substances with high efficiency of sunlight utilization, BiVO₄has been an ideal visible-light-driven semiconductor. While Bi₂WO₆has high chemically stability and do not photocorrode during the photocatalytic oxidation, due to its narrow band gap energy of2.7eV, it can be excited by visible or ultraviolet light, so its development and use will be beneficial to improve the utilization of sunlight.In this paper, the monoclinic scheelite phase BiVO₄was prepared by the liquid phase precipitation method. Orthorhombic polyhedral Bi₂WO₆, orthorhombic spherical Bi₂WO₆, diatomite@BiVO₄and diatomite@Bi₂WO₆were prepared by the liquid phase precipitation method and hydrothermal method respectively.Firstly, with Bi（NO₃）₃-5H₂O and NH₄VO₃as raw materials, the monoclinic scheelite phase BiVO₄was prepared by the liquid phase precipitation method. XRD, SEM, IR were used to investigate the effects of pH, initial concentration of reactants, reaction temperature, reaction time on the structure and morphology of the products, the optimum reaction condition was obtained. The optimum reaction condition of degradation methoxychlor by BiV04was studied.Secondly, orthorhombic polyhedral Bi₂WO₆and ortborhombic spherical Bi₂WO₆were synthesized through the liquid phase precipitation method and hydrothermal method. The structure and morphology of the catalysts were characterized by XRD、 EDS、 SEM、IR、 DRS、 BET. The optimum reaction conditions of degradation methoxychlor by polyhedral Bi₂WO₆and spherical Bi2WO₆were studied. The visible-light photocatalytic activities of polyhedral Bi₂WO₆and spherical Bi₂WO₆in the same condition were coMPared.Finally, on the basis of orthorhombic polyhedral Bi₂WO₆and orthorhombic spherical Bi₂WO₆synthesized by the liquid phase precipitation method and hydrothermal method, diatomite@BiVO₄and diatomite@BbWO₆were prepared with diatomite as raw material. The structure and morphology of the catalysts were characterized by XRD、EDS、 SEM、 IR、 DRS、 BET. With visible-light photocatalytic degradation of methoxychlor as the model reaction, visible-light photocatalytic activities of diatomite@BiVO₄and diatomite@Bi₂WO₆were studied. The degradation products of methoxychlor were determined by GC-MS. And the degradation reaction mechanism was launched.