Atomic Structure Characterization of Au–Pd Bimetallic Nanoparticles by Aberration-Corrected Scanning Transmission Electron Microscopy

Au–Pd core–shell nanoparticles were structurally characterized using spherical aberration (Cs) corrected scanning transmission electron microscopy (STEM). The microscope is equipped with a detector of high-angle annular dark field (HAADF)-STEM, in addition with an energy-dispersive X-ray spectrometer (EDS). The high-resolution elemental line-scan was carried out using the combination of STEM-EDS which allowed us to obtain an elemental analysis at atomic level. The effect of the Pd in the formation of Au–Pd core–shell has been studied by HAADF-STEM images and molecular dynamics studies. The obtained results predict that the growth of Pd on the Au core is through the formation of islands, suggesting a preferential growth of the Volmer–Weber type model.