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 "Vegard's 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.