Synthesis of Cu core Ag shell nanoparticles using chemical reduction method

Dung Chinh Trinh, Thi My Dung Dang, Kim Khanh Huynh, Eric Fribourg-Blanc and Mau Chien Dang

Abstract

A simple chemical reduction method is used to prepare colloidal bimetallic Cu–Ag core–shell (Cu@Ag) nanoparticles. Polyvinyl pyrrolidone (PVP) was used as capping agent, and ascorbic acid (C₆H₈O₆) and sodium borohydride (NaBH₄) were used as reducing agents. The obtained Cu@Ag nanoparticles were characterized by powder x-ray diffraction (XRD), transmission electron microscopy (TEM) and UV–vis spectrophotometry. The influence of [Ag]/[Cu] molar ratios on the formation of Ag coatings on the Cu particles was investigated. From the TEM results we found that the ratio [Ag⁺]/[Cu²⁺] = 0.2 is the best for the stability of Cu@Ag nanoparticles with an average size of 22 nm. It is also found out that adding ammonium hydroxide (NH₄OH) makes the obtained Cu@Ag nanoparticles more stable over time when pure deionized water is used as solvent