Atomic-scale compositional distribution in PtRu nanocatalysts

Bimetallic nanoparticles hold great promise in achieving controlled and well-defined electronic and catalytic properties highly valued in a wide variety of commercial applications. These properties are attained through a controlled interplay between particle size, atomic ordering and composition [1]. However, characterisation of the atomic structure and composition of particles smaller than 5 nm has proved extremely challenging using conventional characterisation techniques, often prohibiting the establishment of unambiguous structure-property relations. Here we use aberration-corrected high-angle annular dark-field (HAADF) scanning transmission electron microscopy (STEM), electron scattering simulations and density functional theory (DFT) to probe the compositional distribution in bimetallic nanoparticles at the atomic scale. The combined theoretical and experimental characterisation allows us to establish a fundamental understanding of structure-properties relations in bimetallic nanoparticle systems