The electronic structure of gold-platinum nanoparticles: Collecting clues for why they are special

We present a density functional study of the electronic and geometric structure of Au-Pt nanoparticles with up to 40 atoms. Our first-principles calculations consistently show a core-shell growth pattern, qualitatively confirming the findings of previous semiempirical calculations. The average bond lengths of small alloy clusters show a "Vegards law" type behavior independent of their specific geometry. We investigate the static electric dipole polarizability, the Kohn-Sham density of states, and the spatial orbital structure as possible indicators for the special, catalysis-relevant electronic properties of Au-Pt particles. Our results show that small changes in the atomic structure may considerably influence the surface properties of nanoalloy particles.