Supercritical fluids: A route to palladium-aerogel nanocomposites

Supercritical carbon dioxide (scCO(2)) is used to prepare novel silica aerogel composites containing nanoparticles of palladium. The material produced has been found to exhibit a Pd loading of 8% by wt. The particles deposited fit within two discrete size ranges of <6 nm and 15 - 20 nm as analysed by XRD and TEM. We demonstrate that scCO(2) may be successfully applied to prepare catalytic support materials based upon aerogels and that the catalyst is active in a continuous flow reactor leading to effective hydrogenation of cyclohexene.