Highly dispersed nickel and palladium nanoparticle silica aerogels: Sol-gel processing of tethered metal complexes and application as catalysts in the Mizoroki-Heck reaction

Highly dispersed Ni and Pd silica aerogels were prepared through sol-gel processes. They have been synthesized by tethering the metal to the silica matrix with the use of the complexing silanes AEAPTS [N-(aminoethyl)aminopropyl] trimethoxysilane or TRIAMIN [N-((aminoethyl)aminoethyl)aminopropyl] trimethoxysilane. The gels were dried with scCO 2 to afford the aerogels. High metal dispersion and small particle sizes were observed through HRTEM and XRD measurements. The organic groups were removed by oxidation and/or pyrolysis. The Pd reduced aerogels containing 15-17% of palladium are good recoverable catalysts in the Mizoroki-Heck reaction. © the Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2006.