Stability of Pt-Modified Cu(111) in the Presence of Oxygen and Its Implication on the Overall Electronic Structure
2013 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 117, no 32, 16371-16380 p.Article in journal (Refereed) Published
The electronic structure and stability of Cu(111)-hosted Pt overlayers with and without the presence of atomic oxygen have been studied by means of core-level spectroscopy and density functional theory (DFT). Because of lattice mismatch, Pt(111) overlayers grown on Cu(111) are compressively strained, and hard X-ray photoelectron spectroscopy together with Pt L-3-edge X-ray absorption spectroscopy (XAS) reveals a pronounced downshift of the Pt d-band owing to the increased overlap of the d-orbitals, an effect also reproduced theoretically. Exposure to oxygen severely alters the surface composition; the O-Cu binding energy largely exceeds that of O-Pt, and DFT calculations predict surface segregation of Cu atoms. Comparing the adsorbate electronic structure for O on unstrained Pt(111) with that of O on Pt-modified Cu(111) using O K-edge XAS and X-ray emission spectroscopy salient differences are observed and calculations show that Cu-segregation to the topmost layer is required to reproduce the measured spectra. It is proposed that O is binding in a hollow site constituted by at least two Cu atoms and that up to 75% of the Pt atoms migrate below the surface.
Place, publisher, year, edition, pages
2013. Vol. 117, no 32, 16371-16380 p.
Physical Chemistry Materials Chemistry Nano Technology
IdentifiersURN: urn:nbn:se:su:diva-93562DOI: 10.1021/jp400486rISI: 000323301100012OAI: oai:DiVA.org:su-93562DiVA: diva2:647558
Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering DE-AC02-76SF00515; Swedish Research Council (VR); Ministry of Education, Culture, Sports, Science and Technology 2009B1751/BL-47XU;
U.S. Department of Energy DE-AC02-76SF00515; Alexander von Humboldt Foundation 2013-09-112013-09-102014-04-01Bibliographically approved