Synthesis And Photocatalytic Characters Of Nanometer-sized ZnO And Compound Powders

ZnO is a kind of important semiconductor material, its bulk material's energy gap is 3.2 eV, corresponding to the ultraviolet light of the wavelength 387nm. For a kind of important photocatalyst, ZnO was one of several semiconductors which could realize quantum size effect, which gained people comprehensive research in recent years. But photocatalytic efficiency of pure ZnO is lower, so it is hard to apply in the engineering. And its photocatalytic efficiency is improved by compounding semiconductors or adulterating, which was researched widely.In recent years, it was introduced that many physical and chemical methods were applied in preparing ZnO or its compounds, such as homogeneous precipitation method, ion beam sputtering, gas phase synthesis, sol-gel. In this paper, ZnO, ZnO/Ag, ZnO/La₂O₃ and ZnO/CeO₂ were prepared by polyacrylamide gel method and solid phase synthesis method. The phase was analyzed by XRD, the particle figure and the size distribution were analyzed by TEM, and whether organic matter was sintered completely through analyzing by FT-IR, and the photocatalytic activity was analyzed through decomposing the solution of methylene blue which was irradiated by the high-voltage mercury lamp and sunlight. The results showed:(1) Nanometer-sized ZnO was prepared at 550℃ by polyacrylamide gel method. Zinc acetate is used as starting material, acrylamide and N,N'-methylenediacrylamide are used as monomer and lattice reagent, and the best weight ratio between them is 5:1. The even size of ZnO is 30-40nm, the specific surface is 26-36m²/g. The methylene blue can be decomposed rapidly by photocatalyzing of ZnO. And the decomposed rate got to 64% after irradiated 2h. In addition, that ZnO photocatalyze methylene blue is first order kinetic model.(2) Nanometer-sized ZnO/Ag was prepared at 550℃ by polyacrylamide gel method. And the photocatalytic activity of ZnO doped noble metal Ag was improved. The optimal pH value is 9.0; and the photocatalytic activity can't be affected by the degradating temperature; the activity is enhanced by adding ammonium persulfate. Furthermore, the optimal content of Ag is 1.0%, which couldn't add surfactants during the preparation. After adding ethylene glycol in the course of preparation, the even particle of ZnO/Ag compound is 25nm, and the decomposed rate got to 100% after...