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

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.Fil: Mayoral, Alvaro. University of Texas; Estados UnidosFil: Mejia Rosales, Sergio Javier. Universidad Autónoma de Nuevo León; México. University of Texas; Estados UnidosFil: Mariscal, Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Pérez-Tijerina, Eduardo. Universidad Autónoma de Nuevo León; MéxicoFil: José-Yacamán, Miguel. University of Texas; Estados Unido