Investigation of alumina aerogel structural characteristics at different «precursor-water-ethanol» ratio

Abstract

Alumina aerogels in the form of monoliths were obtained within a work. Gels were synthesized using a sol-gel process. An inorganic salt, aluminum chloride hexahydrate, was used as a precursor. Hydrolysis and condensation reactions were carried out in a medium of water and ethanol, and epichlorohydrin was the initiator of the gelation process. In order to identify an appropriate compositions of components gels preparation the phase equilibrium of the «epichlorohydrin-ethanol-water» system was experimentally studied. The effect of the precursor-water-ethanol ratio on the aerogels’ final characteristics was investigated. To determine the characteristics of alumina aerogels method of nitrogen adsorption, helium pycnometry, transmission and scanning transmission electron microscopy with x-ray microanalysis were used. The resulting materials have high specific surface area from 464 to 859 m2/g and low density from 65.6 to 121.1 kg/m3. The structure of alumina aerogels consists of flake-like particles which form the interconnected network. Such materials are promising for use as heat-insulating materials and catalysts.