CO Oxidation on Pt-Group Metals from Ultrahigh Vacuum to Near Atmospheric Pressures. 1. Rhodium
| Autor: | D. W. Goodman, Yixuan Wang, Y. Cai, Q. L. Guo, Feng Gao, Kerrie K. Gath, Mingshu Chen |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
Absorption spectroscopy
Inorganic chemistry Analytical chemistry chemistry.chemical_element Atmospheric temperature range Surfaces Coatings and Films Electronic Optical and Magnetic Materials Rhodium Reaction rate chemistry.chemical_compound General Energy X-ray photoelectron spectroscopy chemistry Torr Physical and Theoretical Chemistry Stoichiometry Carbon monoxide |
| Zdroj: | The Journal of Physical Chemistry C. 113:182-192 |
| ISSN: | 1932-7455 1932-7447 |
| DOI: | 10.1021/jp8077979 |
| Popis: | The CO oxidation reaction on Rh(111) was studied both at low pressures (≤2 × 10−4 Torr) under steady-state conditions and at high pressures (0.01−88 Torr) in a batch reactor at various gaseous reactant compositions. Surface CO and O coverages were determined using polarization modulation infrared reflection absorption spectroscopy (PM-IRAS) and X-ray photoelectron spectroscopy (XPS). CO titration experiments were also carried out on surfaces with known oxygen coverages. Both CO and O inhibition were evident at low pressures so that only within a relatively narrow temperature range were the reaction conditions optimized such that the CO conversion reached ∼20% of the CO flux to the surface. For high pressures and with stoichiometric or slightly oxidizing reactant ratios (O2/CO ≤ 2), the reaction fell into three regimes: (i) a CO-inhibited low temperature regime where the reaction rate was determined by CO desorption; (ii) a mass transfer limited regime at high temperatures; and (iii) a transient, high-rate... |
| Databáze: | OpenAIRE |
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