The Co-Au interface in bimetallic nanoparticles: A high resolution STEM study

A. MAYORAL; S. MEJIA-ROSALES; M. M. MARISCAL; E. PÉREZ-TIJERINA; M. J. YACAMÁN

Nanoscale

Royal Society of Chemistry RSC

Año: 2010 vol. 2 p. 2647 - 2651

2040-3364

We report the formation of Au/Co nanoparticles and their characterization by aberration (Cs) corrected scanning transmission electron microscopy (STEM). The nanoparticles were synthesized by inert gas condensation, forming initially core-shell and bimetallic crystals. However, after thermal treatment at normal atmospheric conditions, the Co nanoparticles changed their morphology into a fine layer forming a perfect interface with the gold. The ordering of the zone rich in Co presents a fcc arrangement matching the gold lattice. The atomic analysis on the interface and the comparison of the STEM images with numerical simulations corroborated the atomic substitution of gold by cobalt