Research On Photocatalytic And Antibacterial Properties Of Two Element Co-doped Nano TiO₂ Powder And Thin

Nano titanium dioxide, owned excellent photocatalyst properties, can degrade some kinds of poison to non-toxic subatances and also kill bacteria at the same time. It is used in water treatment and environments disinfection. However, the photo catalyst properties of the materials depend on UV light strongly and also the photo produced electron can easily react with‘hole’. The two problems hinder its wide application. It becomes the urgent thing to be resolved for nano-TiO₂ photocatalytic materials.In order to resolve the problems, in the present paper, the sol-gel method was used to prepare the Fe, Gd co-doped TiO₂ nano-powder and Ag, Zn co-doped TiO₂ film. The XRD, SEM, TEM, TG-DSC, UV-Vis, XPS and experiment of degradation of methyl orange and bactericidl were used to determine the microstructure and properties of the obtained materials. The results were as following:For the Fe, Gd co-doped TiO₂ nano-powder materials, the co-doped method can improve the phase transition temperature, reduce the grain size, and also the powder showed absorption on the visible light region. When the content of additive was small, the response to visible light were the synergies effect of two doped elements; When the content of additive was big enough, the response to visible light was mainly affected by the response to the effect of Fe doping; The obtained materials owned much better photocatalytic activity in visible light region than that of mono-doped TiO₂ or pure TiO₂. It exhibited that the doped powder can not only exhibited the response to visible light but also it can hold back the reaction of the photo produced electron and‘hole’. The optimum doping amount （mass fraction） for the Fe: Gd: TiO₂ was 0.05:0.05:100, the best heat treatment temperature was 550℃, and the corresponding crystal size was 10.23 nm.For the Ag, Zn co-doped TiO₂ thin film, doped Zinc and Silver element can effect the growth of crystal size of TiO₂, the films showed 100% sterilization rate on the condition of light, based on the mechanism of TiO₂ photocatalytic activity and metal ion exposure to sterilization. When in the absence of light, it still got the 99.5% sterilization rate, based on the mechanism of metal ion exposure to sterilization. It showed a high bactericidl rate in the absence of light when the heat treatment temperature was between 450℃and 550℃and the coating times were 3-5 times.