常压干燥法制备TiO_2气凝胶

Preparation of TiO_2 Aerogels by Ambient Pressure Drying

以钛酸丁酯为原料,以甲酰胺为干燥控制化学添加剂控制凝胶网络结构,采用溶胶-凝胶法制得TiO2醇凝胶;结合正硅酸乙酯母液浸泡和低表面张力溶剂替换及常压干燥等后处理步骤,实现了TiO2气凝胶的常压干燥法制备.采用XRD、BET、TEM、SEM、EDS及FT-IR等测试手段对样品进行表征.结果表明:所制备的TiO2气凝胶为无定形结构,表观密度为0.375g/cm3,比表面积达523m2/g,平均孔径约9.9nm;经850℃空气气氛下煅烧4h后,TiO2气凝胶转变为锐钛矿型结构,平均孔径增大到16.3nm,比表面积仍达208m2/g.本研究提出的制备方法简单,所制备的气凝胶比表面积高、热稳定好.

TiO2 aerogels were prepared by sol-gel method at ambient pressure using tetrabutyl titanate as raw material, formamide as drying control chemical additive, tetralthyl orthosilcate（TEOS）/ethanol as pore fluids extractant. The structural properties of aerogel samples were characterized by means of XRD, BET, TEM, SEM, EDS and FT-IR, etc. Experimental results show that asprepared TiO2 aerogel is in amorphous state with the apparent density of 0.375g/cm^3, the specific surface area of 523m^2/g and the average pore size of about 9.9nm. After calcinated at 850℃ in air for 4h, the sampletransforms from amorphous state to anatasetype crystal, while its＇ pore volume shrinks and average pore size increases to 16.3nm, the specific surface area reduces to 208m^2/g. TiO2 aerogel prepared by the above method presents excellent thermal stability and high specific surface area.