Preparation And Photocatakttic Activity Of ZnO Composite Materials From Hydrotalcite

Development of a fabrication process for ZnO semiconductor photocatalysis having high quantum efficiency, wide wavelength absorption scope and film immobilization is essential if their catalytic applications are to be realized in practice. In this work, we show that multi-component composite films based on ZnO have been fabricated by sintering a single-source M(?)ZnAl-layered double hydroxide (LDH) precursor at 500-700℃. The structure, morphology and photocatalytic activity of the resulting films have also been investigated by XRD, FT-IR, TG-DTA, BET, SEM-EDS and UV-Vis techniques. The photocatalytic activity of the composite films was tested using methyl orange and methylene blue as the model reaction. The details are as follows:(1) Cu2+-modified ZnO composite films were obtained by thermal decomposition of Cu/Zn/Al LDH precursors with different initial molar ratio. XRD and SEM-EDS analyses show that ZnO naocrystals are homogeneously incorporated into Al2O3 or ZnAl2O4 nanoparticle matrix containing CuO particle. The effects of preparation conditions on the photocatalytic property of the resulting film were also investigated. The results showed that the Cu2+-modified ZnO/Al2O3 film derived from LDH with initial molar ratio Cu/Zn/Al of 1/6/2 sintered at 500℃has visible-light photocatalytic activity, and the decolorization percentage of methyl orange and methylene blue reached 92.6% and 92.5%, respectively.(2) Co2+-modified ZnO composite films were obtained by thermal decomposition of Co/Zn/Al LDH precursors with different initial molar ratio. XRD and SEM-EDS analyses show that ZnO naocrystals are homogeneously incorporated into Al2O3 or ZnAl2O4 nanoparticle matrix containing Co3O4 particle. The effects of preparation conditions on the photocatalytic property of the resulting film were also investigated. The result indicated the dependence of photocatalytic activity of the ZnO composite film on sintering temperature and initial molar ratio of LDH precursor, Co2+-modified ZnO/Al2O3 film derived from LDH with initial molar ratio Cu/Zn/Al of 1/6/2 sintered at 500℃has UV-and Vis-light photocatalytic activity, and the decolorization percentage of methyl orange and methylene blue were 93.6% and 84.3%, respectively.