Construction of ZnO/Keggin Polyoxometalate Nano Heterojunction Catalyst For Efficient Removal of Rhodamine B in Aqueous Solution

Abstract In this paper, we synthesized two novel heterojunction nanocomposite catalysts ZnO/Ag4SiW12O40 and ZnO/Cs3PW12O40 by a simple dissolution-precipitation method. The structure and morphology of the samples were analyzed by XRD, TEM, FT-IR, Raman, UV diffuse reflection, XPS and N2 adsorption desorption isotherm. Compared with pure ZnO, the composite catalyst formed with Ag4SiW12O40(AgSiW) and Cs3PW12O40(CsPW) can significantly improve the problem of fast recombination rate of photogenerated carriers in ZnO, and broaden the response range of ZnO to visible light. Rhodamine B (RhB) was used as a simulated pollutant to investigate the photocatalytic degradation performance of the composite catalyst. The experimental results show that the photocatalytic degradation activity of the prepared composite catalyst is much higher than that of pure ZnO, and the degradation performance of ZnO/Ag4SiW12O40 is stronger. Finally, the possible photocatalytic mechanism of ZnO/Ag4SiW12O40 and ZnO/Cs3PW12O40 heterojunction nanocomposite catalysts was proposed by UV diffuse reflection, free radical capture experiment and Mott Schottky test.