Investigation On Preparation And Photocatalytic Properties Of Bismuth-containing Metal Oxides

As a new type of semiconductor photocatalyst, bismuth-containing metal oxide hasattracted more attention due to its narrow band gap (Eg=2.4eV, monoclinic phase) andrespond to visible light. Therefore, the research and development of bismuth-containingmetal oxides will improve the utilization rate of solar energy in environment purificationand new energy development, which have potential practical value. In this thesis,bismuth-containing metal oxides (m-BiVO4, BinMomOl) with different morphologies andstructures were prepared by the low temperature combustion method and hydrothermalmethod, respectively. BiVO4/C and BiVO4/TiO2nanocomposites were synthesized byimpregnation method. The morphology, structure and composition of the products werecharacterized by the X-ray powder diffraction (XRD), transmission electron microscopy(TEM), scanning electron microscope (SEM). The UV-Vis diffuse reflection(UV-Vis-DRS) technology was used to study light response of the photocatalyst. TheUV-visible absorption was used to investigate the ability of liquid phase photocatalyticdegradation of organic pollutants. Methylene blue was emloyed as a reaction in this test.The m-BiVO4was prepared by the low temperature combustion method andhydrothermal method, respectively. Meanwhile, the m-BiVO4with different morphologieswas prepared by a simple hydrothermal method adding different surfactants. The resultsshowed that the photocatalytic activity of m-BiVO4was best by a simple hydrothermalmethod adding sodium dodecyl benzene sulfonate (SDBS).The m-BiVO4/C and m-BiVO4/TiO2composites were prepared by impregnationmethod. These photocatalytic activities were examined. The results showed that thephotocatalytic activity of TiO2/m-BiVO4(33%) and m-BiVO4/C (7%) composites weresignificantly higher than BiVO4under the same conditions. On the other hand, themechanisms of improving photocatalytic activity were discussed for TiO2/m-BiVO4andm-BiVO4/C.The bismuth molybdate with different morphologies was prepared by a simplehydrothermal method adding different surfactants or controlling pH value. The results showed that different surfactants and pH have influence on the morphologies andproperties of the material. Meanwhile, the photocatalytic mechanism for degradation ofmethylene blue solution was further explained.