Study About Photocatalytic Ability Of TiO₂ Thin Films Prepared By DC Reactive Magnetron Sputtering Method

The photocatalytic TiO₂ thin films in this thesis were prepared by DC reactive magnetron sputtering technique. Photocatalytic activity of them were evaluated by photocatalytic degradation rate of rhodamine B under the radiation of UV. Technological parameters was optimized by orthogonal experiment.Three series films of sputtering pressure,the distance of the substrate-to-target and substrate temperature were prepared . And then they were given analysis about XRD ,AFM, film thickness and photocatalytic activity . The relations among sputtering pressure ,the distance of substrate-to-target .substrate temperature, thickness , crystal type , crystal diameter and photocatalytic activity of TiO₂ thin film were studied . Whats more the influences of the time for advance adsorption, the primal concentration and pH of rhodamine B to photocatalytic activity of TiO₂ thin film were studied too .The results show that the best conditions obtained is that sputtering power 155W , substrate-to-target distance 85mm,sputtering pressure 0.4Pa,oxygen argon ratiol:10,substrate temperature 550°C.The influence sequence of technological parameters studied to photocatalytic activity of TiO₂ thin film is sputtering pressure ,substrate-to-target distance, oxygen argon ratio, substrate temperature, sputtering power.Sputtering pressure ,substrate-to-target distance ,substrate temperature bring strong influences to thickness , crystal type and crystal diameter of TiO₂ thin film .High thickness ,small crystal diameter and anatase of main crystal type can all enhance photocatalytic degradation rate of TiO₂ thin film,so the final photocatalytic degradation rate depended on the balance of the three factors.Advance adsorption for 1.5h can make rhodamine B adsorbed completely. The photocatalytic degradation rate is heightened after formyl acid is added to rhodamine B solution and it gets the maximum when the pH was 4.0.This result depends on H⁺ can promote reaction between photo-generated electrons and oxygen adsorbed on the TiO₂ thin film,which restrains the recombination of photo-generated holes and electrons and heightens the photocatalytic degradation rate .TiO₂ thin film obtained the highest photocatalytic degradation rate when rhodamine B solution concentration was 25mg.L^-1,beacuse too high concentration will make rhodamine B comparatively superfluous and too low concentration can not exert the photocatalytic activity of TiO₂ thin film .