Novel Preparation of Silver-coated Copper in Aqueous Solution

摘要

Hollow and solid spherical silver-coated copper powders with size of 1μm were facilely prepared by the reduction of silver nitrate in the polyvinyl pyrrolidone (PVP) dispersed copper hydrosol solution at room temperature in the presence of hydrazine hydrate. Scanning electron microscopy and X-ray diffraction were conducted to investigate the formation process of silver-coated copper core-shell particles. The results showed that the absorption and deposition of the Ag nuclei initially occurred at the active sites on the core surfaces as seeds which urged the further deposition of silver species to form sprinkled-structure core-shell particles. During the growth of the silver shell, the dissolution of copper core would result in the formation of hollow spherical particles, while the hydrazine hydrate would help to generate the solid spherical silver-coated copper powders.