CO Adsorption and Disproportionation on Smooth and Defect-Rich Ir(111)
CO adsorption and dissociation on “perfect” and “defect-rich” Ir(111) surfaces were studied by a combination of surface-analytical techniques, including polarization-dependent (PPP and SSP) sum frequency generation (SFG) vibrational spectroscopy, low-energy electron diffraction (LEED), Auger electro...
Gespeichert in:
Veröffentlicht in: | Journal of physical chemistry. C 2022-04, Vol.126 (15), p.6578-6589 |
---|---|
Hauptverfasser: | , , , , , |
Format: | Artikel |
Sprache: | eng |
Schlagworte: | |
Online-Zugang: | Volltext |
Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
Zusammenfassung: | CO adsorption and dissociation on “perfect” and “defect-rich” Ir(111) surfaces were studied by a combination of surface-analytical techniques, including polarization-dependent (PPP and SSP) sum frequency generation (SFG) vibrational spectroscopy, low-energy electron diffraction (LEED), Auger electron spectroscopy, X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) calculations. CO was found to be ordered and tilted from the surface normal at high coverage on the “perfect” surface (e.g., θ = 30° at 0.70 ML), whereas it was less ordered and preferentially upright (θ = 4–10°) on the “defect-rich” surface for coverages of 0.55–0.70 ML. SFG, LEED, and XPS revealed that CO adsorption at low pressure/high temperature and high pressure/low temperature was reversible. In contrast, upon heating to ∼600 K in near mbar CO pressure, “perfect” and even more “defect-rich” Ir(111) surfaces were irreversibly modified by carbon deposits, which, according to DFT, result from CO disproportionation. |
---|---|
ISSN: | 1932-7447 1932-7455 |
DOI: | 10.1021/acs.jpcc.2c01141 |