title: When a Metastable Oxide Stabilizes at the Nanoscale: Wurtzite CoO Formation upon Dealloying of PtCo Nanoparticles.
abstract: Ambient pressure photoelectron and absorption spectroscopies were applied under 0.2 mbar of O2 and H2 to establish an unequivocal correlation between the surface oxidation state of extended and nanosized PtCo alloys and the gas-phase environment. Fundamental differences in the electronic structure and reactivity of segregated cobalt oxides were associated with surface stabilization of metastable wurtzite-CoO. In addition, the promotion effect of Pt in the reduction of cobalt oxides was pronounced at the nanosized particles but not at the extended foil.
authors: †Laboratoire LMSPC, UMR7515 CNRS-Université de Strasbourg, 25 rue Becquerel, 67087 Strasbourg, France.
authors: Vasiliki
authors: V
authors: Papaefthimiou
authors: †Laboratoire LMSPC, UMR7515 CNRS-Université de Strasbourg, 25 rue Becquerel, 67087 Strasbourg, France.
authors: Thierry
authors: T
authors: Dintzer
authors: ‡Laboratoire PMCN UMR 5586, University Lyon 1, CNRS, F-69622 Villeurbanne cedex, France.
authors: Véronique
authors: V
authors: Dupuis
authors: ‡Laboratoire PMCN UMR 5586, University Lyon 1, CNRS, F-69622 Villeurbanne cedex, France.
authors: Alexandre
authors: A
authors: Tamion
authors: ‡Laboratoire PMCN UMR 5586, University Lyon 1, CNRS, F-69622 Villeurbanne cedex, France.
authors: Florent
authors: F
authors: Tournus
authors: §Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
authors: Detre
authors: D
authors: Teschner
authors: §Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
authors: Michael
authors: M
authors: Hävecker
authors: §Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
authors: Axel
authors: A
authors: Knop-Gericke
authors: §Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
authors: Robert
authors: R
authors: Schlögl
authors: †Laboratoire LMSPC, UMR7515 CNRS-Université de Strasbourg, 25 rue Becquerel, 67087 Strasbourg, France.
authors: Spiros
authors: S
authors: Zafeiratos
keywords: alloys; heterogeneous catalysis; nanoparticles; redox chemistry; surface analysis