Study On Preparation And Photocatalytic Activity Of CdS/ZnO Film On Aluminumî—¥

This paper focused on the preparation methods of the CdS/ZnO composite films and visible light photodegradation of these composite films. The ZnO film was prepared on aluminum substrate by cathodic electrodeposition method. The influence of the concentration of Zn2+, the current density and the temperature on the mass desity of the ZnO film was researched. Then the CdS/ ZnO heterojunction composite films were prepared by cathodic electrodeposition of CdS on the ZnO film. The optimum conditions for the preparation of CdS/ ZnO composite films were researched by orthogonal experimental method. The films were characterized by X-ray diffraction(XRD), and ultraviolet visible near infrared spectroscopy(UV-Vis-NIS). With the methyl orange as simulated organic pollutant, the effects of initial concentration, pH value, the volum of H2O2 and the frequency of use on the photocatalytic activity of CdS/ ZnO were studied. The kinetics of photocatalysis process was also researched. The results showed that the rate of photocatalysis degradation can be expressed in first-order kinetics model. The rate constant of reaction was connected with initial concentration and pH of methyl orange solution and added oxidants. The mechanism of the degradation of the methyl orange under visible light irradiation was also studied. It turned out that the photocatalytic activity of CdS/ ZnO composite films was obviously higher than that of a single ZnO film.