Highly dispersed metal nanoparticles in functionalized SBA-15

Abstract

The preparation and characterization of highly dispersed metal nanoparticles in mesoporous silica SBA-15 are reported. The functionalization with organosilane to generate a monolayer of charged groups on the pore surface facilitates uniform distribution of ion-exchanged metal precursors in the channels of SBA-15, which, upon reduction, results in highly dispersed metal nanoparticles supported in SBA-15. Under mild reduction conditions, the surface functionality remains and so allows further metal incorporation cycles to achieve higher metal loading. After reduction in hydrogen flow, disk-shaped Pt nanoparticles in Pt/SBA-15 and spherical Au nanoparticles in Au/SBA-15 have been characterized in the channels of SBA-15 by PXRD, XAS, and TEM. Secondary Pt incorporation in Au/SBA-15 produces coexisting small Pt nanoparticles with large Au nanoparticles in the host channels. This preparation method is capable of template synthesis of various metal nanostructures with controlled morphology and composition inside the channels of mesoporous materials.