Preparation of core-shell nanospheres of silica-silver: SiO2@Ag

摘要

We prepared SiO2@Ag core-shell nanospheres: silver nanoparticles (similar to 4 +/- 2 nm in diameter) coated silica nanospheres (similar to 50 +/- 10 nm in diameter). The preparation route is a modification of the Stober method, and involves the preparation of homogeneous silica spheres at room temperature, combined with the deposition of silver nanoparticles from Ag+ in solution, by using water/ethanol mixtures, tetraethylorthosilicate as Si source and silver nitrate as Ag source in a single-pot wet chemical route without an added coupling agent or surface modification, which leads to the formation of core@shell homogeneous nanospheres. We present the preparation and characterization of the SiO2@Ag core-shell nanospheres and also of bare silica spheres in the absence of silver, and propose a reaction mechanism for the formation of the core-shell structure.