SiO_2对金红石相纳米TiO_2热稳定性的影响

Effect of Silica Dioxide on the Thermal Stability of NanosizedTitanium Dioxide in the Rutile Phase

通过硅酸钠水解生成的无定形SiO2对金红石相纳米TiO2进行表面处理,利用X射线衍射、透射电镜和比表面仪对纳米TiO2进行了表征。结果表明,SiO2沉积在纳米TiO2的表面和颗粒之间。SiO2的表面处理提高了纳米TiO2热稳定性,抑制了TiO2晶粒和一次粒径的长大。当热处理温度低于700℃时,经SiO2处理的纳米TiO2的晶粒尺寸和一次粒径几乎不变;当热处理温度高于700℃时,经SiO2处理的纳米TiO2的晶粒尺寸和一次粒径开始缓慢变大,比表面积和孔容快速下降,在900℃下煅烧2h,经SiO2处理的TiO2一次粒径仍为20～30nm。

The nanosized titanium dioxide in the rutile phase was treated by amorphous silica using sodium silicate as source material to hydrolysis.The nanosized titanium dioxide was characterized by XRD,TEM and BET techniques.The results showed that silica deposited on the surface and gap of nanosized titanium dioxide.The thermal stability of nanosized titanium dioxide was promoted,the crystal grain and primary particles were suppressed from growing in the presence of silica.When the temperature of heat treatment was lower than 700℃,the crystal grain and primary particles of nanosized titanium dioxide treated by silica were almost unchanged.While the temperature of heat treatment was higher than 700℃,crystal grain and primary particles grew slowly,specific surface area and pore volume droped quickly.With calcining at 900℃ for 2h,the primary particle size of nanosized titanium dioxide treated by silica was 20-30nm.