甲酰胺对TiO_2气凝胶微观结构的影响

Effect of formamide on microstructure of TiO_2 aerogel

以钛酸丁酯为钛源,甲酰胺为干燥控制化学添加剂(DCCA),采用溶胶-凝胶法及溶剂置换等后续工艺,结合常压干燥法制备块状TiO2气凝胶,并研究甲酰胺对气凝胶微观结构的影响。采用BET,SEM,XRD及FT-IR等检测方法对样品结构性能进行表征。研究结果表明:采用甲酰胺作为干燥控制化学添加剂制备TiO2气凝胶,可缩短凝胶时间,减小表观密度,提高比表面积,防止凝胶开裂;当甲酰胺与钛酸丁酯的物质的量比为0.8时,制备的块体TiO2气凝胶微观结构最佳,该样品表观密度为0.18 g/cm3,比表面积为579.6 m2/g,平均孔径为19.4 nm,经850℃高温处理后表现出较好的热稳定性及光催化性能。

Monolithic TiO2 aerogels were prepared by sol-gel method and subsequent process with ambient pressure drying, using titanate tetrabutoxide as titanium source and formamide as drying control chemical additives （DCCA）. The effects of formamide on the microstructure of TiO2 aerogels were also investigated. The microstructure and properties of samples were characterized by means of BET, SEM, XRD and FT-IR, etc. The results show that formamide as DCCA of TiO2 aerogels can shorten the gelation time, reduce the apparent density, increase the surface area and prevent the cracking of gel. When the molar ratio of formamide to titanium tetrabutoxide is 0.8, the microstructure of as-prepared monolithic TiO2 aerogel is the best, with the apparent density of 0.18 g/cm3, the specific surface area of 579.6 m2/g and the average pore size of 19.4 nm. After calcined at 850 ~C, the aerogel has high thermal stability and photocatalytic activity.