Preparation And Photocatalytic Properties Of Semiconductor Oxides

Photocatalytic degradation of inorganic and organic toxicants in a semiconductor suspension has been proved to be a feasible method for various pollutants treatment. The complete mineralization pollutants of which was achieved by a relatively short period of illumination in a semiconductor suspension, therefore,this technology has attracted a great deal of attention and many paper had been reported.Many researchers are focusing on study this technology.The vast majority of catalysts used in modern chemical industry are based on mixed metal oxides. Among the mixed metal oxides, perovskite-type composite oxides and spinel-type composite oxides have been widely used in various areas because of their unique optical,electrical and magnetic properties.Also,they possess excellent photocatalytic properties.In this paper,we mainly study preparing,characterization and photocatalytic properties of zinc oxide,perovskite- type composite oxides and spinel-type composite oxides.main contents are as follows:1.Reaction mechanism,characteristic,influencing factors,application,existing problems and development direction of photocatalytic oxidation at semiconductor powders were reviewed. Perovskite-type composite oxides and spinel-type composite oxides were also simply introuduced.2.Nanoscale ZnO were prepared by oxalate precipitation method and citric acid complexometry method.The structure,patterns and size of ZnO were measured by the XRD,SEM and TEM.The photocatalytic properties of the samples were evaluated by degradation of methyl orange. Effects of different preparing methods on structure,patterns and the photocatalytic properties were compared.The results show that ZnO prepared by precipitation method were hollow prismatical structure and the photocatalytic properties was better.3.LaFeO₃ and LaMnO₃ were prepared by citric acid complexometry method. Series catalyzers La_1-xZn_xFeO₃ were prepared by Zn²⁺ doping LaFeO₃. Their phase and patterns were measured by the XRD and TEM. Pb²⁺ doping LaMnO₃ and LaMnO₃ calcined at different temperature were also prepared and characterized by XRD. The effects of A-doping,different calcined temperature and dose of catalyzer on photocatalytic properties of LaMnO₃ were studied.The photocatalytic properties of the samples were evaluated by degradation of the Reactive Brilliant Red X-3B. The results showed that the structures of the samples were all perovskite-types and A-site doping could notably improve the photocatalytic activity of LaFeO₃ and LaMnO₃.4.Spinel-type composite oxides MAl₂O₄(M=Mg,Ni,Zn) and zinc spinel composite oxides ZnM₂O₄(M=Cr,Fe,Co) were prepared by citric acid complexometry method. They were characterized by XRD,TG-DTA,TEM. The effects of temperature on forming spinel-type composite oxides were studied. Their photocatalytic properties were evaluated by degradation of the Rhodamine B. The results showed that the structure of the samples were all Spinel-types.The photocatalytic properties of degradation of RhodamineB were all right.