TiO2颗粒表面包覆SiO2纳米膜及其表征

TiO₂作为一种重要的催化剂，在石油化工方面有重要的应用，特别是煤基合成油和超深度脱硫中的优越性受到注目。同时TiO₂还是重要的白色颜料，为了提高TiO₂的应用性能，对TiO₂颗粒进行了SiO₂纳米膜的表面包覆改性。采用精确控制pH值的连续法在TiO₂颗粒表面包覆了SiO₂的纳米层，并进行了TEM、HRTEM、EDS、XPS、ICP和光学性质表征。证明了SiO₂在TiO₂颗粒表面形成了一层连续的纳米膜，厚度大约为3.5～4.0nm，SiO₂凝胶纳米膜比较致密，没有未包膜上的絮状物，而且TiO₂是单颗粒分散，没有发生多个颗粒被包膜在一起的现象。XPS证明SiO₂凝胶在包膜后的TiO₂颗粒的表面为物理包覆。用SiO₂包膜后，样品的光学性质有了明显的提高，同时改变了样品在不同介质中的分散性质，在水性介质中分散性能提高到93.0％。这种表面处理后的TiO₂可以作为一种催化剂用于煤基合成油和超深度脱硫中。

SiO2 NANOLAYERS AND CHARACTERISTICS COATED ON THE SURFACE OF TiO2 PARTICLES

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