Preparation Of Modified Titanium Dioxide Film And Research On Its Photocatalytic Activity

In recent years, nano-TiO₂was widely used in the area of water treatment due to itsgood photocatalytic activity, nontoxicity, innocuousness, high chemical stability and so on.The TiO₂precusor sol was prepared using tetrabutyl titanate[Ti（OBu）4] as titanium source,absolute ethanol as solvent and HCl as hydrolysis inhibitor. TiO₂film was prepared bydip-drawing and then calcination at 520℃for 2 h and anatase nano-TiO₂film wasobtained. This avoided the problems coming from the difficulty during TiO₂powderrecovery and the high cost in TiO₂powder suspension system. With phenol as the simulantpollutant, its removal was determined after 90 minutes and experimental results show thatphenol removal rate is 16.8 % in UV light, but it is only 3.2 % in visible light.TiO₂films mono-doped and co-doped with Fe,Mn,Ce,Zn,N as dopants and onesadded with a adequate amount of pore-creating agent （polyethylene glycol-400） wereprepared so that their photocatalytic activity would be enhanced in visible light. All thesefilm samples were tested and the results show that:（1） The modified TiO₂has higher specific surface area than that of the pure TiO₂;（2） The photocatalitic activity is better when the molar ratio of Mn/Ti is 2.0 % for allthe mono-doped TiO₂films, the phenol removal rate is 24.2 % in UV light and 7.8 % invisible light, improving by 50 % and 140% respectively than the pure TiO₂films, but theZn-doping is no obvious effect on the photocatalitic activity of TiO₂film both in UV lightand in visible light;（3） All the dopants tested in the study have remarkable cooperation effect on thephotocatalitic activity. For metal co-doped TiO₂fims with a appropriate rate of dopedmetals, its photocatalytic activity can be improved. When molar ratio of Fe/Ti is 0.25 %and Mn/Ti is 2.0 % in the modified TiO₂film, the film has the best photocatalytic activity,the phenol removal rate is 26.2 %, improving by 56 % than the pure one in uv light;（4） All the film samples have stronger light-induced hydrophilicity and betterchemical stability.