Ultrafast formation of hollow Cu@Ag core-shell nanocrystals and their surface-enhanced Raman scattering properties

Abstract

A simple and rapid one-pot synthesis method was developed for producing hollow Cu@Ag core-shell nanocrystals (NCs) in the aqueous phase. The galvanic displacement between Cu NCs and Ag+ took place quickly, leading to the ultrafast formation (within seconds) of hollow Cu@Ag core-shell NCs. The resulting hollow Cu@Ag core-shell NCs were characterized using transmission electron microscope, X-ray diffraction, UV-vis spectroscopy, and X-ray photoelectron spectroscopy. Due to the stronger electromagnetic enhancement and higher light scattering cross-section of Ag NCs than Cu NCs, the hollow Cu@Ag core-shell NCs exhibited significantly enhanced surface-enhanced Raman scattering sensitivity toward crystal violet and superior plasmon-assisted photocatalytic activity in the transformation of p-aminothiophenol to dimercaptoazobenzene.