溶胶-凝胶法制备纳米TiO_2先驱体及其晶型演化研究

Nanoscale TiO_2 Precursors Preparation via Sol-Gel Method and Their Crystal Phase Evolution

以钛酸四丁酯为原料,采用溶胶-凝胶法制备了TiO2先驱体粉末,并采用红外分析、热重-差热分析、X射线衍射等方法对所制得的先驱体和裂解产物进行了表征。结果表明:在纳米TiO2先驱体粉末的制备过程中,乙酸作为钛酸四丁酯水解溶液的稳定剂参与抑制水解,在pH=3的溶胶中,—OR基被醋酸部分取代为聚合的醋酸钛;先驱体粉末在275℃时发生醇缩聚与失水缩聚,失重率达30%;在450℃时发生锐钛矿向红宝石的晶型转向;在900℃时金红石的质量分数约为90%,锐钛矿的质量分数约为10%;400℃时晶粒尺寸为18nm,900℃时为21nm,晶粒尺寸随着温度的上升而变大。

TiO2 nanoparticle precursors were prepared by a sol-gel process using Ti（OC4H9）4 as raw material, and also were characterized by IR, XRD, TG-DSC. The results of infrared absorption spestra show that the acetate replaces the OR group and is directly bound to titanium hydrolysis while the pH=3. The alcohol condensation and dehydration condensa- tion of precursors powder happened at 275 ℃, the weightlessness rate was 30%. The anatase to ruby crystal type steering occurred in 450 ℃. In 900 ℃ ruffle content is about 90%, the anatase content is approximately 10%. The grain size is 18 nm in 400 of 2 and 21 nm in 900 ℃. The grain size becomes bigger with increasing temperature.