In situ Formation of Palladium Nanoparticles Inside the Pore Channels of Ordered Mesoporous Silica

Palladium-containing SBA-15 (SBA-15-Pd) was synthesized via an in situ approach. In this procedure, molecular assembly template was employed as a hydrophobic carrier to provide the compatible environment for the hydrophobic compounds. The hydrophobic solvent (CHCl3) was used as a transport medium to inject the Pd precursor (Pd(acetylacetonate)(2)) directly into the inner core of the surfactant micelles. A 1.46 wt% Pd loading was achieved without the loss of pore ordering. Highly dispersed and uniform palladium nanoparticles could be detected using transmission electron microscopy confirming also the absence of large particles outside the mesopore silica. The catalytic activities of the SBA-15-Pd nanocomposites were investigated in Heck coupling reactions with activated and non-activated aryl substrates. The SBA-15-Pd nanocomposites exhibit excellent catalytic activities and reuse ability in air for the Heck carbon-carbon coupling reactions.