Novel synthesis of gold nanoparticles supported on functionalized silica

Recently, we presented stable silica-supported gold nanoparticles (AuNPs) suitable for catalysis, obtained by using as the only reactants a gold precursor, chloroauric acid (HAuCl4), and commercial polyethyleneimine-functionalized silica beads (SiO2-PEI), with the need for neither external reducing agents nor conventional stabilizing moieties. [1] In this work we describe another convenient method to prepare silica-supported gold nanoparticles. The silica nanoparticles were synthetized, first, by co-condensation of tetraethoxysilane and an organo-silane alkyne-terminated (SiO2-Yne), [2] and then post-functionalized by thiol/yne coupling with cysteamine (SiO2@Thio-Yne). By simply adding the obtained systems to an aqueous solution of HAuCl4 the spontaneous formation of AuNPs was observed in both cases and in very short times with diameters in the range of 10 to 20 nm. These new systems were fully-characterized by FT-IR, XPS spectroscopy, DLS , UV-Vis and TEM microscopy.