Preparation And Photocatalytic Activity Of Deposited Bi <2 WO <6> Catalysts

Research of photocatalytic degradation of organic waste water has become one focus in the field of environment.The current research mainly about TiO2photocatalyst TiO2due to its good catalytic activity, light stability, non-toxic and has always been the focus of attention.Because its forbidden band width is bigger (Eg=3.2eV), visible light response is weak, for sunlight utilization rate is not high, and limits the practicability of TiO2.New type, high efficiency, can make full use of the development of visible light catalyst the attention of many scholars.Bismuth tungstate (B12WO6) due to its response to visible light has a good range is becoming a hot spot of research.Tungsten acid bismuth, however, as with the simple oxide layer structure, the high rate of compound in the electron and hole seriously inhibits its photocatalytic performance, Kudo study has found that since1999the Bi2WO6in lambda420nm> show good photocatalytic activity under visible light irradiation, the Bi2WO6photocatalyst research more and more, especially for Bi2WO6photocatalyst activity to further improve the proposed many methods.In this paper the preparation conditions of roasting temperature on the photocatalytic activity of Bi2WO6influence, and carries on the doping modification of metal elements and oxides, further improve the photocatalytic activity.The experiment by means of XRD, SEM, BET and Uv-vis modern characterization techniques such as the catalyst grain structure, microstructure, specific surface area and light response ability have been characterized, and for degradation of rhodamine B (RhB), under the visible light photocatalytic degradation experiment to optimize the preparation process.Finally, the Bi2WO6photocatalyst active mechanism has carried on the preliminary discussion.In this paper the main research contents and results are as follows:(1) Bi2WO6photocatalyst was prepared by hydrothermal synthesis method series, in determining the optimal hydrothermal conditions (pH4.5, hot water temperature160℃, hydrothermal time12h) on the basis of further examines the roasting temperature and the influence of structure activity of Bi2WO6.By XRD, SEM, BET and UV-vis analysis indicates that the roasting temperature on the morphology of catalyst samples, particle characteristics, structure, etc, has a larger effect; Calcination temperature is300℃, the catalytic properties of tungsten acid bismuth, best to get the sample of the crystallinity is like a large surface area, increase the response of the visible light range(2) Under the condition of the preparation of the metal (Fe) and metal oxide (Ag2O) doped Bi2WO6photocatalyst, and the different doping amount and roasting temperature on the photocatalytic degradation of RhB research, according to the results;Iron doping amount is0.5%calcination temperature is200℃when the RhB degradation rate of97%;Silver oxide doped with10%when roasting temperature is350℃RhB degradation rate of98%.(3) the combination of different characterization results, the paper analyzes the different calcination temperature and doping quantity will effect the performance of the catalyst.(4) Through the loop experiment BiiWO6, Fe-Bi2WO6, Ag2O-Bi2W06three different stability of the catalyst, results show that the stability of Ag2O-Bi2WO6is higher than, Fe-Bi2WO6are better than that of without doping Bi2WO6catalyst.And reasoning mechanism, the influence of dopants for catalyst reaction mechanism and put forward many shells.