Thermal stability of Cu@Ag core–shell nanoparticles

Abstract

In this study, the structural evolution and oxidation of Cu@Ag core–shell nanoparticle deposits (withaverage particle diameter of 25 nm and Ag/Cu atomic ratio of 1/8) upon heating in air were investigatedquantitatively via in situ synchrotron radiation X-ray diffraction. With an increasing temperature, thecoalescence of Cu cores and ripening of Ag shell occurred simultaneously, resulting in discrete Ag nanonodulesand unprotected Cu microparticles. Due to the protection of the thin Ag shell, the formation temperaturesof the Cu oxides for Cu@Ag NPs were higher than those for pure Cu nanoparticles with similarsize by at least 150 C