Facile synthesis of mesoporous gold-silica nanocomposite materials via sol-gel process with nonsurfactant templates

Mesoporous gold-silica nanocomposites have been synthesized through simple one-step sol-gel reactions of tetraethyl orthosilicate (TEOS) with a gold sol in the presence of dibenzoyl tartaric acid (DBTA) as a nonsurfactant template. The gold nanoparticles were incorporated into the three-dimensional silica network through the sol-gel process to afford monolithic crack-free DBTA-containing gold-silica gels. After removal of DBTA by calcination at 550 °C, annealed mesoporous gold-silica nanocomposites were obtained. The pore structure parameters were investigated by means of nitrogen sorption isotherm, X-ray diffraction, and transmission electron microscopy (TEM). The results indicate that the mesoporous structure of the gold-silica nanocomposites has high surface areas up to 630 m 2 /g, large pore volume of ∼0.5 cm3/g, and pore diameters of 3-4 nm with relatively narrow pore size distributions. With use of energy-dispersive X-ray (EDX) elemental analysis, the compositions of the gold-silica composite materials were quantitatively measured. The effects of gold content on the pore parameters have been addressed. The TEM and X-ray mapping images show that gold particles in the range of 2-8 nm are homogeneously distributed throughout the silica matrixes for all the samples. The surface plasmon resonance of gold nanoparticles was also investigated.