Electronic and structural study of Pt-modified Au vicinal surfaces: A model system for Pt-Au catalysts

Mauricio J. Prieto, Emilia A. Carbonio, Shadi Fatayer, Richard Landers, Abner De Siervo

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

Two single crystalline surfaces of Au vicinal to the (111) plane were modified with Pt and studied using scanning tunneling microscopy (STM) and X-ray photoemission spectroscopy (XPS) in ultra-high vacuum environment. The vicinal surfaces studied are Au(332) and Au(887) and different Pt coverage (θPt) were deposited on each surface. From STM images we determine that Pt deposits on both surfaces as nanoislands with heights ranging from 1 ML to 3 ML depending on θPt. On both surfaces the early growth of Pt ad-islands occurs at the lower part of the step edge, with Pt ad-atoms being incorporated into the steps in some cases. XPS results indicate that partial alloying of Pt occurs at the interface at room temperature and at all coverage, as suggested by the negative chemical shift of Pt 4f core line, indicating an upward shift of the d-band center of the alloyed Pt. Also, the existence of a segregated Pt phase especially at higher coverage is detected by XPS. Sample annealing indicates that the temperature rise promotes a further incorporation of Pt atoms into the Au substrate as supported by STM and XPS results. Additionally, the catalytic activity of different PtAu systems reported in the literature for some electrochemical reactions is discussed considering our findings. © 2014 The Owner Societies.
Original languageEnglish (US)
Pages (from-to)13329-13339
Number of pages11
JournalPhysical Chemistry Chemical Physics
Volume16
Issue number26
DOIs
StatePublished - Jul 14 2014
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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