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

Abstract

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 744.5m2/g and low density of 0.063g/cm3. The specific surface area of the aerogel is gradually reduced with the increase of heat treatment temperature, but it is still as high as 153.45m2/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.

Keywords

• alumina aerogel
• sol-gel
• chelating reagent
• heat treatment
• specific surface area