Preparation And Visible Light Responsive Photocatalytic Activity Of Bismuth-based Oxysalts/Layered Double Hydroxide Composites

In recent years, photocatalysis using semiconductor materials as photocatalysts have attracted increasing attention. It can be used for the degradation of organic pollutants under visible light or UV light irradiation. Research show that the technology was in possession of the prominent virtues, such as low cost, simple to operate, degradation products is no toxic, no secondary pollution and so on. Among the various semiconductor photocatalysts,Bi-based semiconductors have been report to exhibit interesting photocatalytic activities,such as Bi₂WO₆, Bi₂MoO₆. However, the photocatalytic efficiency of single semiconductor is not sufficient for practical applications because of its low quantum yield. This is caused by the rapid recombination of photoinduced electrons and holes. Therefore, it is meaningful to improve the photocatalytic activities of Bi-based semiconductor.In this research, Bi₂ MoO₆ and Bi₂WO₆ were prepared by solvothermal,Bi₂ MoO₆/Ni-Fe LDH and Fe₃O₄/Ni-Al-Ce LDH/Bi₂WO₆ composites were prepared by co-precipitation. The morphology and structure of the sample were characterized by XRD,Raman, FT-IR, SEM, TEM, XPS, UV-vis diffuse reflectance spectra, N2-physisorption.The magnetism of Fe₃O₄/Ni-Al-Ce LDH/Bi₂WO₆ composites is analyzed and studied by VSM techniques.Photocatalytic degradation activity and mechanism of the samples were investigated by the photocatalytic degradation of methyl orange（MO）, methylene blue, butyl rhodamine B and phenol under visible light irradiation. The results showed that BET specific surface area of the composites increased with the LDH content increase.Photocatalytic degradation activity of MO under visible irradiation exhibited significant enhancement. And the composites photocatalytic degradation followed first-order reaction kinetics. The composites decolorizing rate still remained 88% after 5 times recycle,showing high catalytic stability. Photocatalytic activity were investigated by the photocatalytic degradation of methyl orange（MO） under visible light irradiation. The results showed that BET specific surface area of the composites increased with the Ni-Al-Ce LDH content increase. Compared with pure Bi₂WO₆ and Ni-Al-Ce LDH, the composites exhibit a significant enhanced photocatalytic activity. The composites degradation efficiency still remained 71% after 4 times recycle, showing high catalytic stability.