Alkoxide-free sol–gel synthesis of aerogel iron–chromium mixed oxides with unique textural properties

Abstract

Aerogel chromium–iron mixed oxide with equimolar amounts of both metals was prepared by a sol–gel method using nitrate salts of both metals. Propylene oxide was used as an efficient gelation promoter and supercritical CO2 was employed for solvent extraction from the gel. The calcined mixed oxide showed significantly higher surface areas, larger pore volume, and enhanced thermal stability as compared with its xerogel counterpart and the corresponding single-metal oxides. Textural properties were compared at various calcination temperatures and unique textural properties were observed after calcinations at 350°C.