高比表面积、低密度块状Al2O3气凝胶的制备及表征

Preparation and characterization of Al2O3 bulk aerogel with high specific surface area and low density

以仲丁醇铝(ASB)为前驱体,乙醇为溶剂,乙酸为催化剂,乙酰乙酸乙酯(Etac)为螯合剂,通过溶胶-凝胶和超临界干燥过程制备得到块状氧化铝气凝胶,并在不同温度下对其进行热稳定性分析。此外,通过SEM,XRD,FT-IR和N 2吸附-脱附分析等测试研究了乙醇和乙酰乙酸乙酯的用量对氧化铝气凝胶微结构及比表面积的影响。结果表明:氧化铝气凝胶具有叶片状颗粒堆积形成的纳米多孔网络结构,比表面积高达744.5m^2/g,密度低至0.063g/cm^3,随着热处理温度升高,比表面积逐渐降低,1200℃热处理2h后依旧高达153.45m^2/g;经不同温度热处理后,氧化铝气凝胶的叶片状多孔结构未发生明显变化,表明该氧化铝气凝胶具有高温稳定性。

We report a facile approach to synthesize alumina aerogel through sol-gel reaction followed by supercritical drying,in which ASB is as co-precursors,EtOH as solvents,Etac as chelating reagent,HAc as catalysts.The as-prepared aerogel was treated at different temperatures.Moreover,the effect of the amount of ethanol and chelating agent ethylacetoacetate on the microstructures of aerogels and the changes of specific surface areas under different conditions were also discussed by SEM,XRD,FT-IR,TG-DTA and nitrogen adsorption-desorption.The results indicate that the monolithic alumina aerogel has nanoporous network structure consisted of randomly connected leaf-like particles,which also has high specific surface area of 744.5m^2/g and low density of 0.063g/cm^3.The specific surface area of the aerogel is gradually reduced with the increase of heat treatment temperature,but it is still as high as 153.45m^2/g after 2h treatment under 1200℃.After heat treatment at different temperatures,the leaf-like porous structure of alumina aerogel does not change significantly,indicating that this alumina aerogel has high temperature stability.