Preparation And Photocatalytic Performance Of Titanium Dioxide Film

TiO₂ thin film avoids the disadvantages that suspended TiO₂ has when applied to photo catalysis organic pollutants, such as being inactivated and integrated easily, difficult to separate and recycle. It is widely studied in the application of environmental remediation, antimicrobial gelatin and self-cleaned materials. At present, the technological application of TiO₂ films seems limited by the lower photo catalytic activity and the lower efficient use of solar light. In this paper, the photo catalytic TiO₂ thin film is obtained on the glass substrate by sol-gel and dip-coating method. And the photo catalytic performance of TiO₂ thin film is also studied.Firstly, the photo catalytic TiO₂ thin film is obtained on the substrate of glass by sol-gel and dip-coating method in which tetrabutyl titanate is used as the precursor, ethanol as the solvent, acetic acid as the catalyst, triethanolamine as the complexant and the polyethylene glycol is added finally. By studying the influence of the factors on the film thickness, transmittance, adherence with the substrate in the preparing process, the optimal preparing conditions is got as follows: the proportion of the materialsn(Ti(OC4H9)4):n(C2H5OH):n(H2O)=1:22:7, the quantity of PEG is 10% of the mass of tetrabutyl titanate, heated at 500℃for 2 hours. The film prepared in the optimal preparing conditions is composed of anatase phase and is uniformly composed of particles of which the diameter is less than 100 nm.Secondly, the factors such as deposited times, ultraviolet source, dissolved oxygen, the number of deposited glass, the initial concentration of Rhodamine B, an irradiation time, doping, washing which influenced the TiO₂ photo catalysis are investigated. With the increase of the deposited times, the thickness of the film is increased, and the degradation efficiency also increases. When deposited four times, the degradation efficiency is the best. The ultraviolet source plays an important role in the reaction. That is because the main oxidant·OH can be formed in the presence of ultraviolet source. The dissolved oxygen not only can increase the contact probability between the surface of TiO₂ film and the Rhodamine B molecule, but also can improve the catalytic efficiency by producing·OH.