Abstract: As an important catalyst,TiO₂ is widely applied in petrochemical industry,especially,in coalbased synthesized oil and superdeep desulphure,meanwhile,TiO₂ is also important raw material of white pigment.In order to improve the application function of TiO₂,surfacecoating modification of SiO₂ nanolayers is done to TiO₂ particles.The continuous method precisely controlling PH value is used to coat SiO₂ nanolayers on the surface of TiO₂ particles,and TEM,HRTEM,EDS,XPS,ICP and optical property are characterized.It is proved that a continuous SiO₂ nanolayer forms on the surface of TiO₂ particle with thickness of some 3.5~4.0nm,the SiO₂ gel nanolayer is quite tight without floccus on noncoated film,and the TiO₂ is dispersed in the shape of single particle,there is no the occurance particles being coated together.XPS indicates SiO₂ gel on the surface of TiO₂ particle after coating is physically coated.After coating,the optical property of SiO₂ sample is apparently improved,and the dispersing property of the sample in different media is changed,in water,the dispersing ability increases to 93.6%.The surface treatment,as a catalyst,can be used in coalbased synthesized oil and superdeep de sulphure

Key words: TiO2, SiO2, gel, nanolayers