金红石二氧化钛表面二氧化硅纳米膜成膜机理

Formation mechanism of nanosilica film on rutile TiO_2

研究以硅酸钠为原料,利用液相沉积法在以硫酸氧钛为原料制备的金红石型二氧化钛表面包覆二氧化硅纳米膜。使用透射电镜分析二氧化钛表面二氧化硅包覆膜的形貌,结合红外光谱与X射线光电子能谱分析技术研究金红石型二氧化钛表面包覆二氧化硅纳米膜的成膜过程以及成膜机理。以激光粒度测定仪分析二氧化硅包覆二氧化钛样品在水溶液中的分散程度。实验表明,二氧化硅包覆层与基底二氧化钛之间存在Si—O—Ti键。将反应液pH值控制在不同的范围内可以在二氧化钛颗粒表面包覆不同形貌的二氧化硅包覆层,形成岛状膜或连续致密膜。粒径分析表明二氧化硅包覆能够很好地提高二氧化钛的分散程度。

SiO2-coated TiO2 powders were prepared by chemical deposition method starting from rutile TiO2 and Na2SiO3. The SiO2-coated TiO2 powders were characterized by X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy and laser particle size instrument, The formation mechanism of the nanosilica film on TiO2 surface was investigated, The silica coating layers were anchored on TiO2 surfaces via the Ti---O---Si bonding at the interface, The evolution of island-like coating and uniform coating layers depend upon reaction temperature and pH. After coating, the dispersibility of SiO2-coated TiO2 powders in water is promoted.