title: Core-shell compositional fine structures of dealloyed Pt(x)Ni(1-x) nanoparticles and their impact on oxygen reduction catalysis.
abstract: Using aberration-corrected scanning transmission electron microscopy and electron energy loss spectroscopy line profiles with Ångstrom resolution, we uncover novel core-shell fine structures in a series of catalytically active dealloyed Pt(x)Ni(1-x) core-shell nanoparticles, showing the formation of unusual near-surface Ni-enriched inner shells. The radial location and the composition of the Ni-enriched inner shells were sensitively dependent on the initial alloy compositions. We further discuss how these self-organized Ni-enriched inner shells play a key role in maintaining surface lattice strain and thus control the surface catalytic activity for oxygen reduction.
authors.affiliation: The Electrochemical Catalysis, Energy and Materials Science Laboratory, Department of Chemistry, Technical University Berlin, 10623 Berlin, Germany.
authors.forename: Lin
authors.initials: L
authors.lastname: Gan
authors.forename: Marc
authors.initials: M
authors.lastname: Heggen
authors.forename: Stefan
authors.initials: S
authors.lastname: Rudi
authors.forename: Peter
authors.initials: P
authors.lastname: Strasser