Synthesis And Characterization Of Zinc Oxide And Copper Oxide With Controlled Morphology

ZnO is a n-type semiconductor with a wide direct band gap of 3.3eV at room temperature,exciton binding energy of 60meV,and a hexagonal wurtzite structure of space group P6₃mc.CuO is a p-type semiconductor with a narrow band gap of 1.2eV at room temperature,and a monoclinic system of space group C2/c.Both ZnO and CuO are applied on gas sensors,UV light detection,catalyst and electrode materials in batteries for their good physic properties,such as conductive,photoelectric and so on.In recent years, morphologies of ZnO and CuO crystals have attracted great attention.However,few articles with regard to Zn-Cu composite oxides with microstructure have been reported lately.Zinc oxides,copper oxides and Zn-Cu composite oxides with different morphologies were prepared in our works.The effect of synthesis condition on crystal growth and structure formation mechanisms were discussed.The photo-catalysis and the capacitance properties of single oxide were compared with composite oxides.1.ZnO or CuO with different morphologies were prepared by a chemical precipitation method and hydrothermal mute.The morphology of oxides can controlled through adjusting reaction conditions.ZnO with various morphologies of single rod,bundled rods with more arms,hexagonal nanorod,nanotube,nanosheet and needle-like nanorods were synthesized.CuO prepared possess some special morphology such as cauliflower structure, global structure,nanobelt,feather-like structure and nanosheet.Photocatalysis performance and capacitance ability of ZnO can be affected greatly by morphology.ZnO with single rod prepared by(CH₂)₆N₄ showed optimal photocatalysis performance,by which methylene blue can degrade completely after three hours.Specific capacitance of CuO with flowerlike structure prepared by(CH₂)₆N₄ is the highest among CuO with different morphologies, and the value is 133.56F/g.2.CuO loading on ZnO nanorod was prepared by chemical precipitation method, impregnation method and solid state grinding.In chemical precipitation method,when ZnO nanorod prepared by ammonia is used as carrier,Cu²⁺ can enter into ZnO crystal lattice and morphology of ZnO is not destroyed.In the process of impregnation method and solid state grinding method,the surface of ZnO nanorod was covered with CuO particles. Results show that photocatalysis performance of ZnO is decreased by addition of CuO,and capacitance properties of ZnO electrode can be improved by the addition of CuO.Specific capacitance of Zn-Cu composite oxides prepared by chemical precipitation method,solid state grinding and impregnation method are 13.66F/g,19.11 F/g and 25.29F/g respectively. These values are respectively 147%,245.6%å’Œ357.3%higher than that of ZnO rod-like (5.53F/g).3.When CuO nanobelt was used as carrier,ZnO loading on CuO were prepared by chemical precipitation,impregnation method and solid state grinding method.In the chemical preparation method,Zn²⁺ can enter into CuO crystal lattice and long flake shape which is same as morphology of carrier was formed.When impregnation method and solid state grinding method were used,ZnO grains and nanosheets were be formed respectively, and existed among the long flakes.Specific capacitances of Zn-Cu composite oxides prepared by impregnation method are 133.9F/g and 84.18%higher than CuO nanobelt (72.7F/g).