Sol - Gel Prepared By Zno Thin Films And Its Photocatalytic Properties

With the advancement and development of modern industry, increasing environmental problems are brought out. There are many methods for disposing contaminations, among which the multiphase photocatalysis for the degradation of contaminations is superior. This method has high activity, no selectivity, complete oxidation, sunlight and oxygen's application (in water phase). It can be applied for hard degradation. American, Japan and Canada use the technology of photocatalysis for environmental protection. But now, the research level of this technology is limited in the laboratories in China.This thesis includes four parts of work:1.ZnO thin films were prepared by sol-gel in glass substrate, and were characterized by XRD, AFM, SEM, UV-VIS, DSC-TGA and FTIR.2.By using the azocarmine of certain dye wastewater as the objective decomposition substance and using eorthogonal experiment method, the influences of annealing temperature, coating layer number, original concentration, and pH value of solution on the degradation of were studied.3.Using La³⁺and Fe³⁺modifled ZnO thin films, and the influences of light response of ZnO and photocatalystic activity were discussed.4.The influences of electric field to photocatalystic activity were discussed in different ways of electric field.The results show that the ZnO films prepared by sol-gel are hexahedron structure, with the increasing of temperature, the grain size of the ZnO increases in 17 to 30 nanometers, film surface consists of well-dispersed laminated shape ZnO crystals, and the roughness of ZnO thin films is large. The films absorption limits were about 380nm, and the absorption in the visible light region cannot be observed. The annealing temperature of 300℃, coating number of 5 and original pH of 8～9 are the best conditions in photocatalytic experiment. The La³⁺ and Fe³⁺ doping modified ZnO photocatalysis' absorbing bounds moved, the films surface became more smoother, and their photocatalytic activities were enhanced with different degree. Different ways of electric field affected photocatalytic activities with different degree, and in our experiment, when the the anode bias voltage is 20V, the degradation efficiency can be greatly increased.In addition, a lot of problems which have been caused by those experiments were illuminated and analyzed in the last chapter of this paper. Moreover, further research direction was pointed out.