Investigating the mechanism of uniform Ag@SiO2 core-shell nanostructures synthesis by a one-pot sol–gel method

Abstract

Monodispersed Ag@SiO2 core-shell structure nanoparticles (NPs) are synthesized at room temperature via a one-pot sol–gel synthesis method, and the synthesizing procedure is observed over reaction time in order to investigate the formation mechanism. Ostwald ripening of silver (Ag) core NPs and silica (SiO2) shells during synthesis of core-shell NPs proceeds in parallel to reaction time. Uniform and stable Ag@SiO2 core-shell NPs are formed at 48 h of reaction time. The hydrolysis rate of tetraethyl orthosilicate (TEOS) plays a critical role in the growth of Ag NPs and the final structure of Ag@SiO2 core-shell NPs. The formation mechanisms of single-core and multicore Ag@SiO2 core-shell NPs are discussed in relation to synchronous Ag core and SiO2 shell growth. Optimal reaction conditions for critical parameters (water volume and TEOS and ascorbic acid concentrations) are also determined.