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CO dissociation on clean and hydrogen precovered Fe(111) surfaces
- Source :
-
Journal of Catalysis . Jul2007, Vol. 249 Issue 2, p174-184. 11p. - Publication Year :
- 2007
-
Abstract
- Abstract: Spin-polarized density functional theory calculations were performed to investigate CO dissociation on clean and hydrogen precovered Fe(111) at 1/3 monolayer coverage. On clean Fe(111), the adsorbed CO first diffuses from the shallow-hollow site to the bridge-like site by elevating 0.20 eV in energy, and then dissociates into C and O atoms by overcoming a barrier of 1.53 eV. Interestingly, the CO dissociation process is accelerated in the presence of H2 via intermediate CHOads (COads + 2Hads → CHOads + Hads → CHads + Oads + Hads). This stepwise path is kinetically more favored with the lowest barrier of 1.17 eV. In contrast, the previously suggested paths, COads + 2Hads → Cads + Oads + 2Hads and COads + 2Hads → Cads + OHads + Hads, are not competitive due to higher barriers (1.76 and 1.79 eV, respectively). The activity of different low-index Fe surfaces toward CO is also compared. [Copyright &y& Elsevier]
- Subjects :
- *HYDROGEN
*ATOMS
*DENSITY functionals
*NONMETALS
Subjects
Details
- Language :
- English
- ISSN :
- 00219517
- Volume :
- 249
- Issue :
- 2
- Database :
- Academic Search Index
- Journal :
- Journal of Catalysis
- Publication Type :
- Academic Journal
- Accession number :
- 25616614
- Full Text :
- https://doi.org/10.1016/j.jcat.2007.04.018