纳米TiO_2制备过程中乙醇含量对其性能的影响

Effect of Ethanol Content on the Performance of Nanosized TiO_2 During Preparation

以钛酸丁酯(TBOT)为原料,采用溶胶-凝胶法制备TiO_2溶胶,研究TiO_2溶胶制备过程中乙醇用量的变化对溶胶粘度、密度、稳定性、粒径分布的影响,考察溶胶内部的化学结构和TiO_2的物相转变情况。结果表明:随着乙醇含量的增加,溶胶的粘度、密度、Zeta电位减小;当醇钛物质的量比小于50时,溶胶平均粒径相差不大且粒径分布较窄,当醇钛物质的量比大于50时,平均粒径随乙醇含量的增加而增大,且粒径分布变宽;所制备的TiO_2溶胶内部结构以Ti-O-Ti键为主,所形成的TiO_2分子具有线性结构。TiO_2溶胶真空干燥后,其粉末晶型为无定型态,经350℃焙烧后,纳米TiO_2转变为锐钛矿型。

The TiO2 sol have been prepared using the sol-gel method by tetrabutyl titanate （TBOT） as the raw material. The influence of ethanol content on the sol viscosity, density, stability, particle size distribution were investigated during the preparation of TiO2 sol. The internal chemical structure and phase transition of TiO2 sol were discussed. The results showed that, with the increasing of ethanol content, the sol viscosity, density and zeta potential were decreased. As the alcohol to titanium molar ratio was less than 50, the difference between mean particle size was less and the sol particle size distribution became narrow. While the alcohol to titanium molar ratio was more than 50, the mean particle size increased with ethanol content increased and the sol particle size distribution became wide. Analysis showed that Ti-O-Ti bond was the primary structure of TiO2 sol. The TiO2 powder was amorphous state after vacuum drying and it turned into anatase type after calcined at 350 ℃.