Preparation And Performance Of Self-cleaning Nano-TiO₂ Coating

Transparent TiO₂ hydrosol and Fe-TiO₂ hydrosol,which could be mixed with water and used directly for coating,were prepared by sol-gel method,with Ti(OBu)₄ as precursor.The relationship between the concentration of Fe and its photocatalytic activity was studied by the degradation rate of methylene blue(MB).The composition and microstructure of samples were studied by X-ray photoelectron spectroscopy(XPS),differential thermal analysis(DTA), X-ray diffraction(XRD),and transmission electron microscopy(TEM).The results showed that,the photocatalytic degradation effect of hydrosol samples under UV irradiation was better than solar irradiation,while the effect of power samples was adverse.On the same condition,the photocatalytic degradation effect of Fe-TiO₂ hydrosol and powder was better than that of TiO₂ hydrosol and powder under UV and solar irradiation. When the weight ratio of Fe/TiO₂ was 0.03%,the photocatalytic decomposition rate was the highest.The results of structure analysis revealed that,TiO₂ transformed from amorphous to anatase at 415.7℃,and anatase transformed ruffle gradually at 470℃.The doping of Fe made anatase more stable and could prevent the phase change from anatase to rutfle.The phase was amorphous,anatase and rutile when the heat treatment temperature of TiO₂ was 200℃,500℃, and 700℃.The doping of Fe could not make TiO₂ form new phase.The particle sizes of TiO₂ and Fe-TiO₂ were in the range of 10nm～14nm.When the weight ratio of Fe/TiO₂ was 0.03% the dispersion of nanometer particle was best.