Preparing highly-dispersed noble metal supported mesoporous silica catalysts by reductive amphiphilic molecules

Abstract

We present an in situ reduction strategy to prepare mesoporous silica supported by highly-dispersed noble metals. First, an amphiphilic molecule with ferrocenyl as a reductive hydrophobic terminal group was designed and synthesized. Next, we used it as a structure-directing agent to self-assemble into mesoporous silica. Then the amphiphile remaining in the mesoporous channels could in situ reduce gold or palladium salts into corresponding metal nanoparticles. Finally, the amphiphile was removed through calcination. The mesoporous structure and the highly-dispersed Au or Pd nanoparticles were confirmed through XRD and TEM. The reducibility of the amphiphile was proved by XPS, and was further verified by cyclic voltammetry and thermodynamic calculation. BET analysis showed that the mesoporous catalysts have a specific surface area of over 900 m² g⁻¹. The catalysts showed significantly higher catalytic activities in the reduction of 4-nitrophenol and the Suzuki reaction than those prepared via traditional impregnation methods.