CO Adsorption and Disproportionation on Smooth and Defect-Rich Ir(111).
Xia LiThomas HaunoldStefan WerkovitsLaurence D MarksPeter BlahaGünther RupprechterPublished in: The journal of physical chemistry. C, Nanomaterials and interfaces (2022)
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.
Keyphrases
- density functional theory
- molecular dynamics
- high resolution
- single molecule
- high temperature
- aqueous solution
- healthcare
- magnetic resonance imaging
- solid state
- electron microscopy
- escherichia coli
- electron transfer
- computed tomography
- biofilm formation
- crystal structure
- pseudomonas aeruginosa
- cystic fibrosis
- candida albicans
- monte carlo
- energy transfer