Abstract
Infrared reflection absorption spectroscopic (IRRAS) measurements were conducted for carbon monoxide (CO) adsorption on Pt(111) bimetallic surfaces with various thicknesses of deposited Ni, i.e., Nix/Pt(111) (x, Ni thickness in nanometer units), which were fabricated using molecular beam epitaxy at substrate temperatures of 343-473 K. The reflection high-energy electron diffraction (RHEED) patterns for the 343-K-deposited Ni 0:1nm-0:6nm /Pt(111) reveal Ni epitaxial growth on Pt(111). The CO exposure to the clean Pt(111) surface at 323 K engenders linearly bonded and bridge-bonded CO-Pt bands at 2093 and 1858 cm-1. The 343-K-deposited Ni0:1nm /Pt(111) gives rise to a new band at 2070 cm-1 in addition to the CO-Pt(111) bands. T he new band is most prominent for the Ni0:3nm /Pt(111), on which the bridge-bonded CO on the Ni admetal layer appears at 1874 cm-1. For the Ni0:6nm /Pt(111), the 2070 cm-1 band decreases in intensity and the bridge-bonded CO on the Ni admetal-layerdominates the spectrum, with accompanying weak absorption at 2035 cm-1 caused by linearly adsorbed CO on the Ni layer. The low-energy electron diffraction (LEED) pattern for the 343-K-deposited Ni 0:3nm /Pt(111) shows incommensurate higher-order extra spots surrounding integer spots. In contrast, the incommensurate pattern changes to its original six-fold symmetry for the 473-K-deposited Ni0:3nm /Pt(111). In contrast, the RHEED pattern for the 473-K-deposited Ni 0:3nm /Pt(111) revealed streaks having slightly wider separations than those for the clean Pt(111). The IRRAS spectrum for the 1.0-L-CO exposed 473-K-deposited Ni0:3nm /Pt(111) reveals single-absorption at 2074 cm-1. We discuss the CO adsorption behavior of Nix/Pt(111) .
Original language | English |
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Pages (from-to) | 230-233 |
Number of pages | 4 |
Journal | e-Journal of Surface Science and Nanotechnology |
Volume | 7 |
DOIs | |
Publication status | Published - 2009 Apr 4 |
Keywords
- Infrared absorption spectroscopy
- Nickel
- Platinum
- Surface alloy
- Vibrations of adsorbed molecules
ASJC Scopus subject areas
- Biotechnology
- Bioengineering
- Condensed Matter Physics
- Mechanics of Materials
- Surfaces and Interfaces
- Surfaces, Coatings and Films