title: Towards the elucidation of the high oxygen electroreduction activity of PtxY: surface science and electrochemical studies of Y/Pt(111).
abstract: We have prepared an yttrium modified Pt(111) single crystal under ultra-high vacuum conditions, simulating a bulk alloy. A Pt overlayer is formed upon annealing the crystal above 800 K. The annealed structure binds CO weaker than Pt(111), with a pronounced peak at 295 K in the temperature programmed desorption of CO. When depositing a large amount of yttrium at 1173 K, a (1.88 × 1.88)R30° structure relative to Pt(111) was observed by low energy electron diffraction. Such an electron diffraction pattern could correspond to a (2 × 2)R30° structure under 6% compressive strain. This structure is in agreement with the structure of the vacancies in a Pt Kagomé layer in Pt5Y rotated 30° with respect to the bulk of the Pt(111). The Pt overlayer is relatively stable in air; however, after performing oxygen reduction activity measurements in an electrochemical cell, a thick Pt overlayer was measured by the angle resolved X-ray photoelectron spectroscopy depth profile. The activity of the annealed Y/Pt(111) for the oxygen reduction reaction was similar to that of polycrystalline Pt3Y.
authors.affiliation: Center for Individual Nanoparticle Functionality, Department of Physics, Technical University of Denmark, Building 312, DK-2800 Lyngby, Denmark. ifan.stephens@fysik.dtu.dk ibchork@fysik.dtu.dk.
authors.forename: T P
authors.initials: TP
authors.lastname: Johansson
authors.forename: E T
authors.initials: ET
authors.lastname: Ulrikkeholm
authors.forename: P
authors.initials: P
authors.lastname: Hernandez-Fernandez
authors.forename: M
authors.initials: M
authors.lastname: Escudero-Escribano
authors.forename: P
authors.initials: P
authors.lastname: Malacrida
authors.forename: I E L
authors.initials: IE
authors.lastname: Stephens
authors.forename: I
authors.initials: I
authors.lastname: Chorkendorff