Preparation Of Ag-doped TiO₂Film By Sol-gel Method With Pine-coating Technology And Investigation Of Properties

In this paper, Ag/TiO₂thin films were prepared on glass by sol-gel method withpine-coating technology, and the photocatalytic activity of coated glass was evaluated.Through orthogonal analysis, the factors of silver content, spin speed, heating rate,heat-treatment temperature and holding time were investigated. The structure, and phasetransformation of Ag/TiO₂films were studied by X-ray diffraction, Raman and differentialscanning calorimetry; the contact angles of the films were also investigated; thetransmittance of the films was studied by UV-Vis.Better photocatalytic degradation of methyl orange solution was observed in Ag/TiO₂thin film compared with pure TiO₂thin film, the degradation rate of the optimumcombination was89%, but the degradation rate of pure TiO₂prepared in the samecondition was only61%.The order of influencing degradation rate is silver content, heating rate, spin speed,heat-treatment temperature, holding time. The optimum combination is silver content4mol%, spin speed3000r/min, heating rate4℃/min, heat-treatment temperature200℃,and holding time30min.The doping of Ag higher the temperature of shift of anatase to rutile, the peak of rutilecould be observed in the pure TiO₂when heat treated at500℃, but the peak of rutile couldnot be observed in the Ag/TiO₂treated at the same condition. The results of DSC-TGrevealed that the doping of Ag decreased the temperature of anatase arising, thetemperature droped from329℃of pure TiO₂to315℃. It was revealed that the grain sizeof4mol%Ag/TiO₂heat treated at200℃was the least, the grain size is8.9nm. The contactangles of the films turned larger from15°to38°. The Ag/TiO₂films prepared by sol-gelmethod with pine-coating technology were transparent, the transmittances were above75%. The transmittance got high with the spin speed larger, but the transmittance wouldlower when the heat treated temperature turned high. The contact angles reduced with theincrease of the heat-treated temperature.