Synthesis and characterization of pure and yttrium-containing alumina aerogels

Abstract

Various pure and yttrium-containing alumina aerogels have been synthesized and characterized by different techniques. The presence of yttrium promotes the thermal resistance of solids, as demonstrated by X-ray diffraction (XRD) and Brunauer–Emmett–Teller (BET) surface measurements. Yttrium allows the aerogel structure to persist in the θ-alumina form up to 1250–1300°C, whereas the absence of this element gives rise to the α-alumina phase at 1150°C. The role of yttrium obviously is to stabilize the transition alumina structure at high temperature. The direct consequence of this is a well developed texture at high temperature (i.e. 88 m² g^–1 at 1200°C). Such materials could be of interest as catalytic supports for combustion reactions, which are very useful for the regulation of emission pollutants during fuel combustion. On the other hand, the maintenance of a well developed and controlled texture at high temperature could make these solids very attractive as ceramic precursors in the formation of highly densified materials.