PtxGd alloy formation on Pt(111): Preparation and structural characterization

Elisabeth Therese Ulrikkeholm, Anders Filsøe Pedersen, Ulrik Grønbjerg Vej-Hansen, Maria Escudero Escribano, Ifan Stephens, Daniel Friebel, Apurva Mehta, Jakob Schiøtz, Robert K. Feidenhansl', Anders Nilsson, Ib Chorkendorff

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Pt x Gd single crystals have been prepared in ultra high vacuum (UHV). This alloy shows promising catalytic properties for the oxygen reduction reaction. The samples were prepared by using vacuum deposition of a thick layer of Gd on a sputter cleaned Pt(111) single crystal, resulting in a ∼63nm thick alloy layer. Subsequently the surfaces were characterized using X-ray photoelectron spectroscopy (XPS), low energy electron diffraction (LEED), ion scattering spectroscopy (ISS) and temperature programmed desorption (TPD) of CO. A Pt terminated alloy was observed upon annealing the sample to 600 (ring operator)C. The LEED and synchrotron XRD experiments have shown that a slightly compressed (2 ×2) alloy appear. The alloy film followed the orientation of the Pt(111) substrate half the time, otherwise it was rotated by 30(ring operator). The TPD spectra show a well-defined peak shifted down 200 (ring operator)C in temperature. The crystal structure of the alloy was investigated using ex-situ X-ray diffraction experiments, which revealed an in-plane compression and a complicated stacking sequence. The crystallites in the crystal are very small, and a high degree of twinning by merohedry was observed.
Original languageEnglish
JournalSurface Science
Volume652
Pages (from-to)114-122
ISSN0039-6028
DOIs
Publication statusPublished - 2016

Keywords

  • Alloy formation
  • Platinum alloys
  • Single crystals
  • X-ray diffraction

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