Mixed-metal oxide aerogels for oxidation of volatile organic compounds

Aerogels of 100% silica, 8 wt% Zr in silica, 5 wt% V in silica and 100% zir conia were synthesized and tested as oxidation catalysts in the temperature range of 300-700 degrees C for destruction of volatile organic compounds. The silica-based aerogels were all amorphous and had surface areas above 60 0 m(2)/g after oxidation. The zirconia aerogel was crystalline with a relat ively low surface area of 250 m(2)/g. As catalysts for oxidation (using O-2 in He) of CH3OH to CO2, the zirconia aerogel exhibited the highest activit y and best selectivity while the silica aerogel exhibited the poorest. Incl usion of Zr at levels as low as 8 wt% into the silica aerogel framework pro duced activities and selectivities which were very much like the zirconia a erogel. These properties have the impact of producing a Zr based catalyst w ith high activity, but with thermal stability afforded by Zr-silica mixture s. (C) 2000 Elsevier Science B.V. All rights reserved.