Synthesis And Properties Of Tungstate And Molybdate Composite Photocatalytic Materials

In dealing with pollution, photocatalysis as an emerging pollution treatment technology recent years has drawn extensive attention and research due to it can degrade pollutants completely, do not produce secondary pollution and has simple process equipments. Wolframate and molybdate have received widespread attention because of theirs unique structural properties and physical and chemical properties,optical properties in many photocatalysts. In this paper, we modified the cadmium molybdate and zinc tungstate. All samples were prepared by hydrothermal method,characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM),UV-visible diffuse-reflection spectra (DRS), X-ray photoelectron spectroscopy (XPS)and Raman spectroscopy,the photocatalytic activity and photocatalytic mechanism were tested at last, the specific research as follows:1. We studied the photocatalytic activity and mechanism of cadmium molybdate and graphene composite photocatalyst. We used a facile one-step solvothermal method for the synthesis of CdMoO4-graphene composite photocatalysts. It showed that, the adsorption and the photocatalytic performance were improved due to the graphene , result showed that there was an optimal amount of 2.5%.2. We studied the photocatalytic activity and mechanism of zinc tungstate and bismuth tungstate composite photocatalyst. ZnWO4-Bi2WO6 compounds series were successfully prepared using one-step hydrothermal methold, composite improved the separation rate of photogenerated electrons and holes, the photocatalytic effect showed the best when the molar ratio of Zn to W was 1.5:100, holes played a very important role in the photocatalytic process.3. We studied the effect of pH for the structure, physical chemistry and photocatalytic activity of zinc tungstate. The results showed that the crystalline form of ZnWO4 was the best and the photocatalytic efficiency was also highest when pH=8, so the ZnWO4 that we used was pH=8. The ZnWO4 was doped with metal element of bismuth and barium, after photocatalytic degradation experiments, the results showed that the photocatalytic effect of 3at% Bi and 1.5at%Ba doped ZnWO4 were the best and theirs photocatalytic mechanism were studied.