Study On Preparation And Photocatalytic Properties Of Some Semiconductor Photocatalysts

semiconductor photocatalytic technology has the advantages of high efficiency, stability, environmental protection, and has a good application prospect in solving the energy and environmental issues. The development of high efficient photocatalytic materials with wide spectrum response is the core to achieve the semiconductor photocatalytic technology for industrial application. In recent years,more and more researchers focus on the research to develop new efficient visible light response of the catalyst and they has achieved the certain achievements. However,there are lots of unknown in the relationship between photocatalytic system and catalytic performance.On the one hand, this paper improved and optimized the preparation method of new photocatalyst CuBi₂O₄ on the basis of previous studies,and the method is more simple, energy saving and green. In addition, CuBi₂O₄ composition and magnetic carrier catalyst were studied and we got high efficiency and easy separation photocatalyst. On the other hand, the paper modified Zn S to improve its photocatalytic activity and prepared Zn S/Cu₂S composite photocatalyst.The main research contents and results are as follows:（1）The nanocrystalline CuBi₂O₄ was successfully prepared by a ball-milling step using Bi（NO3）3·5H₂O, Cu（NO3）2·3H₂O and Na OH as initial reactants without any other additives. The results show that the crystallinity and the crystal size of CuBi₂O₄ are affected by the reaction time and the CuBi₂O₄ was characterized SEM、TEM、UV-vis.（2） A novel CuBi₂O₄/MWCNT composite was facilely synthesized via a ball-milling process for 2h at room temperature for the first time. The structure, morphology and composition were characterized with powder X-ray diffraction（XRD） and transmission electron microscopy（TEM）. The photocatalytic activity was evaluated by a degradation experiment. The results showed that the CuBi₂O₄ with nanorod structure was welldeposited on MWCNT, and the CuBi₂O₄/MWCNT composites exhibited higher photocatalytic activity than pure CuBi₂O₄. Among the developed composites, 20wt%MWCNT incorporated CuBi₂O₄ composite displayed optimal photocatalytic activity for degradation of methyl orange（MO） under visible light irradiation in comparison to pure CuBi₂O₄ and other composites. The degradation rate of methyl orange can reach 90%after 2h visible light irradiation. Finally, we analysed the reasons for the increase of photocatalytic activity of CuBi₂O₄/MWCNT composite photocatalyst.（3） Using Fe₃O₄ as the carrier, Fe₃O₄/CuBi₂O₄ composite photocatalysts with different CuBi₂O₄ contents were successfully prepared through a ball milling method.The as-prepared samples were characterized by XRD, SEM, TEM. MO was used as the model substance to evaluate the photocatalytic activity of the photocatalysts. The results indicated that Fe₃O₄/CuBi₂O₄ exhibited higher photocatalytic activity than the pure CuBi₂O₄. The effect of loading amount of CuBi₂O₄ on the catalytic performance of the composites was also investigated and the optimal content of CuBi₂O₄ was 40%.Finally, we analysed the reasons for the increase of photocatalytic activity of Fe₃O₄/CuBi₂O₄ composite photocatalyst from the specific surface area.（4） A facile one-pot route for preparing the visible-light-driven Zn S/Cu₂S composites photocatalysis has been developed in our work. The as-synthesized samples are characterized by XRD,SEM, TEM. The results show that their phase composition,crystallinity and the crystal size are affected by the reaction temperature, the reaction time and the initial concentration. MO was used as the model substance to evaluate the photocatalytic activity of the photocatalysts. The results indicated that Zn S/Cu₂S exhibited higher photocatalytic activity than the pure Zn S.