title: The structure of AuPd nanoalloys anchored on spherical polyelectrolyte brushes determined by X-ray absorption spectroscopy.
abstract: Well-defined and facetted bimetallic gold-palladium nanoalloys have been synthesized and anchored in spherical polyelectrolyte brushes (SPB) as composite particles (AuPd@SPB). These particles are better catalysts in aqueous phase than the pure metals. The atomistic arrangement of these nanoalloys has been analysed by extended X-ray absorption fine structure (EXAFS) spectroscopy at the Au-L3 and the Pd-K absorption edge. The samples with high amounts of gold appear as almost statistically mixed random alloys. Alloy compositions with less gold show slight enrichment of Pd at the surface of the particle. In addition, signals of non-metallic palladium appear at the Pd-K edge which indicate the presence of the Pd2+ species in addition to metallic palladium. The relation of these structural features to the catalytic activity is discussed.
authors.affiliation: F-12 Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin, Hahn-Meitner-Platz 1, 14109 Berlin, Germany.
authors.forename: Julian
authors.initials: J
authors.lastname: Kaiser
authors.forename: Wojciech
authors.initials: W
authors.lastname: Szczerba
authors.forename: Heinrich
authors.initials: H
authors.lastname: Riesemeier
authors.forename: Uwe
authors.initials: U
authors.lastname: Reinholz
authors.forename: Martin
authors.initials: M
authors.lastname: Radtke
authors.forename: Martin
authors.initials: M
authors.lastname: Albrecht
authors.forename: Yan
authors.initials: Y
authors.lastname: Lu
authors.forename: Matthias
authors.initials: M
authors.lastname: Ballauff