Surface structure and relaxation at the Pt3Sn(111)/electrolyte interface
In situ surface X-ray scattering (SXS) measurements have been performed to determine the surface structure of Pt3Sn(111) in sulfuric acid electrolyte. Potentiodynamic measurements indicate that the ultra high vacuum (UHV) prepared p(2 x 2) alloy surface structure is stable upon transfer to electrolyte and remains stable during subsequent cycling of the applied potential. A detailed structural study by crystal truncation rod (CTR) analysis shows that the surface layer of Pt and Sn atoms undergoes an expansion of {approx} 2 percent of the (111) layer spacing at low potential (0.05 V vs. reversible hydrogen electrode) in CO-free electrolyte. At 0.55 V the expansion of the Pt atoms is reduced to {approx} 0.6 percent, whereas the Sn atoms are expanded by {approx} 6 percent of the layer spacing. The potential-induced buckling of the surface layer is also observed in CO-saturated electrolyte and is a precursor to Sn dissolution which occurs at {approx} 1.0 V, causing irreversible roughening of the surface.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Director. Office of Science. Office of Basic Energy Sciences. Materials Science and Engineering Division, Division of Chemical Sciences; Engineering and Physical Sciences Research Council (US)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 827969
- Report Number(s):
- LBNL-55922; R&D Project: 505601; 500901; TRN: US200426%%1029
- Journal Information:
- Surface Science Letters, Vol. 544; Other Information: Journal Publication Date: 2003; PBD: 29 Jul 2004
- Country of Publication:
- United States
- Language:
- English
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