Adjustable Dispersive Property of the Nanocomposite of Gold Nanoparticles in Amino-functionalized Mesoporous Silica Thin Films

Highly ordered amino-functionalized mesoporous silica thin films(MTFs) were directly synthesized by co-condensation of tetraethoxysilane(TEOS) and 3-aminopropyltriethoxysilane(APTES) in the presence of P123 (EO20PO70EO20). According to the neutralization-reaction mechanism followed by a reduction procedure of hydrogen-ambience calcinations, gold nanoparticles were introduced into the pore channels of amino-functionalized MTFs, and the Au/SiO2 nanocomposite was Obtained. The nanomaterials were characterized by XRD, TEM, and UV-Vis. It was found that removing the surfactant by ethanol extraction, but not by calcination, could get well-ordered mesoporous structures; gold nanoparticles grew in a preferred orientation of (111) plane of the face-centered-cubic structure in the pore channels and crystallized nicely; the absorption spectrum of Au/SiO2 nanocomposite underwent a red-shift as the reaction time increase, which proves a quantum size effect of gold nanoparticles exists, and dipping time could regulate the dispersive property of Au/SiO2 nanocomposite.