Preparation And Photo-catalytic Performance Of TiO₂ Thin Films

Photo-catalytic TiO₂ thin films illustrate a good prospect of application as a kind of green environmental protection material in the area of air purification, waste water treatment, bacillus resistance, pollution elimination, mist prevention and self-cleanness. In this study, a kind of nano-TiO₂ thin films was prepared on Al/Steel by sol-gel method and dip-coating techniques. And then its caking and photo-catalysis property were studied.TiO₂, made from the former body of Ti(OC₄H₉)₄, was calcined at different temperature from room temperature to 1000℃under experiment, and the phase transformation temperature was detected by XRD in the process of calcinations. The result shows that the phase transformation occurs from anatase TiO₂ to rutile TiO₂ at the temperature from 700℃to 900℃. According to this result, it is most possible to prepare anatase TiO₂ with strong adhesion at low temperature.Using sodium silicate and silica sol as solvent, TiO₂ thin film was prepared by adding anatase TiO₂ into the sol at experiment, and its caking and photo-catalysis property were tested. The thin film made by sodium silicate sol is thicker, and the TiO₂ content in it is higher than by silica sol, but the photo-catalytic effect of the late TiO₂ thin film is better than the former. The silica sol is easy to shrink to form crack when it's heated.At last, Ti(OC₄H₉)₄ was used as the former body, adding catalyst as CH₃COOH, NH₃H₂O, PEG6000 to improve the sol's property. It was found that the dispersibility of TiO₂ could be improved sharply by adding the PEG6000, and its caking property was fine. It could control the hydrolyse and polymerize of the Ti(OC₄H₉)₄ forming fine organic solvent by adding catalyst. The films prepared by this method possess fine bonding and photo-catalytic properties. The effect of the films in killing bacillus E.coli can reach 90%, and also the effect of the films in greasy dirt degradation can achieve 80% in 10 hours illumination.