SYNTHESIS AND CHARACTERIZATION OF SILICA-SILVER CORE-SHELL NANOPARTICLES

Abstract

Silica-silver core-shell nanoparticles have received tremendous interests in various applications compared to the bare silver nanoparticles due to several important features such as exhibit higher surface area, the existence of a synergistic effect between the core and the shell, stabilize silver nanoparticles against aggregation, and easily control their properties by the changing shell structure and shell geometry. Due to this significance, this study was conducted to synthesis and characterization of silica-silver core-shell nanoparticles using the facile method without any surface modification needed. In the synthesis route, silica particles have been synthesis based on the Stӧber method. The deposition of nanoscales silver layer on silica surface mainly involves the electrostatic attraction between [Ag(NH3)2] ions and silanol groups, and the addition of polyvinylpyrrolidone (PVP) has been acted as a reducing agent and stabilizing agent. UV-Vis spectroscopy evidenced the absorption of surface plasmon resonance (SPR) of silver nanoparticles in the range 380-450 nm. The crystallinity of silica-silver core-shell nanoparticles showed the facecentered cubic (fcc) structure by X-ray powder diffraction (XRD) analysis. The spherical shape of silica particles with an average 200-220 nm in size has been determined using scanning electron microscope (SEM). The high resolution-transmission electron microscope (HR-TEM) images visualized the successful formation of spherical silver nanoparticles on the silica surface with the average of size 10-40 nm. X-ray photoelectron spectroscopy analysis revealed the elemental compositions exist in the silica-silver core-shell nanoparticles. The synthesized silica-silver core-shell nanoparticles will be used as a potential catalyst in dye treatment application in the future work.