LayeredClay Aerogels by a Freeze-Drying Process fora Platinum-Supported Catalyst.

Weprepared a clay aerogel by freeze drying an aqueous viscoussuspension of a synthetic saponite (a layered clay mineral of thesmectite family). The nanostructure and texture of the resulting aerogelvaried with the freezing conditions. The freeze drying resulted inmicroporous aerogels with well-ordered (stacked) silicate layers.A fine texture was observed after freeze drying of a starting suspensionat a lower concentration. Freezing in liquid propane yielded a well-definedcontinuous network texture. Toluene in vapor phase was oxidativelydecomposed in air flow over aerogels on which platinum was depositedby an impregnation wetness method; the decomposition was probablyaffected by the size distribution of micropores. [ABSTRACT FROM AUTHOR]