Core-shell structure ZrO2-Al2O3 aerogels prepared by one-step drying under constant pressure

Abstract

drying. In the preparation process of Al2O3 hollow spheres, different mole of ZrOCl2ꞏ8H2O was added. We explored the maximum addition of zirconium via ambient pressure drying. A series of ZrO2-Al2O3 aerogels with hollow sphere structure are successfully synthesized using AlCl3ꞏ6H2O and ZrOCl2ꞏ8H2O as aluminum and zirconium precursor, and propylene oxide (PO) as the gel initiator by the sol-gel method. It was found that the gelation time was prolonged with increasing zirconium content. When the zirconium content was more than 10%, the gel can't be obtained. It can only get precipitation. With the zirconium content increase from 0 to 10%, the core-shell structure can be formed, proved by SEM and TEM characterizations. The core-shell structure can be kept well under 1000°C. When the heat treatment temperature was at 1200°C, the diffraction peaks were mainly ZrO2 and Al2O3, showed by XRD. With the content of zirconium increase from 0 to 10%, the specific surface area of XZrO2-Al2O3-aerogel increased from 170 to 582 m2/g.