A novel approach to Au@SiO2 core-shell spheres

A novel synthesis method was described to prepare Au@SiO2 core-shell spheres, using a commercial gold colloid and tetraethyl orthosilicate as the precursors. The synthesis concept was based on surface modification of the gold nanoparticles with a binary system of surfactants, or using both of 2-Mercapto-ethanol and (3-Aminopropyl)-trimethoxysilane together, and the Stöber processing. The shape and size, and silica coatings of the resultant particles were investigated by transmitting electron microscopy (TEM). The Au@silica core-shell spheres, each containing a single gold nanoparticle or an aggregate of several gold nanoparticles at the center, could be prepared.