Abstract
A hybrid of Ag nanoparticle (NP)-embedded thin silica-coated graphene oxide (GO@SiO&sub2;@Ag NPs) was prepared as a surface-enhanced Raman scattering (SERS) substrate. A 6 nm layer of silica was successfully coated on the surface of GO by the physical adsorption of sodium silicate, followed by the hydrolysis of 3-mercaptopropyl trimethoxysilane. Ag NPs were introduced onto the thin silica-coated graphene oxide by the reduction of Ag⁺ to prepare GO@SiO&sub2;@Ag NPs. The GO@SiO&sub2;@Ag NPs exhibited a 1.8-fold enhanced Raman signal compared to GO without a silica coating. The GO@SiO&sub2;@Ag NPs showed a detection limit of 4-mercaptobenzoic acid (4-MBA) at 0.74 μM.