Synthesis of Ag@Ag2S Core-shell Nanoparticles by Gas-Solid Reaction

Ag@Ag2S core-shell nanoparticles were synthesized by a two-step method. Firstly, silver nanoparticles were prepared by a solvothermal method using anhydrous ethanol as the reducing agent, PVP (K-30) as dipersant and AgNO3 as raw material; Secondly, Ag@Ag2S core-shell nanoparticles were synthesized by the sulfidization of Ag nanoparticles in vacuum atmosphere. The samples were characterized by UV-visible absorption spectroscopy (UV-vis), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The results show that Ag@Ag2S core-shell nanoparticles with an average diameter of 100 +/- 30 nm are synthesised by vapor(S)-solid(Ag) reaction at 80 degrees C for 20 similar to 80 min with S vapor from evaporation of S powder at 450 degrees C.