Preparation And Performance Of Zno Photocatalyst And Ag₂O/ZnO Composite Photocatalyst

ZnO is a new type of semiconductor photocatalyst. It has excellent catalytic property,stable chemical property, a large absorption range of light, nontoxtic, cheep and available.It can decompose the organic pollutants into carbon dioxide and water. In the view of water pollution problem, ZnO plays an important role.In this paper, ZnO photocatalyst was synthesized in the method of hydrothermal and solvent, respectively. Ag2O/ZnO composite photocatalyst was prepared in the hydrothermal method. The as synthesized samples were characterizated by SEM, TEM,EDS, XRD, FT-IR means. The photocatalytic degradation of rhodamine B solution experiment was the probe reaction for evaluating of the above catalyst photocatalytic performance, and the obtained results are as follows:ZnO photocatalyst can be successfully prepared by the two methods, and the crystal type is the six-cubic structure, high crystalline. ZnO prepared in the hydrothermal method present the morphology of thin sheet and needle like, irregular boundary, the partricle size is about 200 nm. The proper preparation conditions of ZnO in the method are as follows:ethanol is the solvent, CTAB is as surfactant, its dosage is 0.05 mol/L, concentation of Zn(Ac)2 is 0.5 mg/L, raw materials ratio(Zn2+/OH-) is 1:4, the crystallization time is 4 h,the crystallization temperature is 120 ℃. When the concentration of rhodamine B solution is 4 mg/L, the dosage of ZnO photocatalyst is 0.04 g, the decolorization rate of rhodamine B can be up to 98.65%.Compared with the above samples, ZnO prepared in the solvent method appear thick sheet morphology, the partricle size is about 100 nm. The proper preparation conditions of ZnO in the method are as follows: ethanol is solvent, OP-10 is as surfactant, the dosage is0.05 mol/L, raw materials ratio(Zn2+/OH-) is 1:4, the crystallization time is 4 h, the crystallization temperature is 140 ℃. When the concentration of rhodamine B solution is 4mg/L, ZnO photocatalyst dosage is 0.04 g, the decolorization rate of rhodamine B can be more than 99%.Ag2O/ZnO composite photocatalyst was prepared in the hydrothermal method, and Zn(NO3)2, AgNO3 and NaOH are the raw materials, the composite photocatalyst presentmainly pencil like structure, the length to diameter ratio is between 20 to 30. Ag2 O particals are evenly attached on the surface of ZnO. Due to forming p-n heterostructure of the composite, the separation of electrons and holes are effectively suppressed, then the photocatalytic performance of the composite photocatalyst can be improved obviously.The proper preparation conditions are as follows: Zn(NO3)2 is as the source of zinc, the raw materials ratio(Ag+/Zn2+) is 0.075:1, the crystallization time is 2 h, the crystallization temperature is 140 ℃. When the concentration of rhodamine B solution is 4 mg/L, the dosage of Ag2O/ZnO composite photocatalyst is 0.04 g, rhodamine B decoloring rate can be up to 99%.