Thermal stability of Cu@Ag core-shell nanoparticles

In this study, the structural evolution and oxidation of Cu@Ag core-shell nanoparticle deposits (with average particle diameter of 25 nm and Ag/Cu atomic ratio of 1/8) upon heating in air were investigated quantitatively via in situ synchrotron radiation X-ray diffraction. With an increasing temperature, the coalescence of Cu cores and ripening of Ag shell occurred simultaneously, resulting in discrete Ag nano-nodules and unprotected Cu microparticles. Due to the protection of the thin Ag shell, the formation temperatures of the Cu oxides for Cu@Ag NPs were higher than those for pure Cu nanoparticles with similar size by at least 150 degrees C. (C) 2013 Elsevier Ltd. All rights reserved.