Oxygen-Promoted Methane Activation on Copper
The role of oxygen in the activation of C–H bonds in methane on clean and oxygen-precovered Cu(111) and Cu2O(111) surfaces was studied with combined in situ near-ambient-pressure scanning tunneling microscopy and X-ray photoelectron spectroscopy. Activation of methane at 300 K and “moderate pressur...
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Veröffentlicht in: | The journal of physical chemistry. B 2018-01, Vol.122 (2), p.855-863 |
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Hauptverfasser: | , , , , , , , |
Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | The role of oxygen in the activation of C–H bonds in methane on clean and oxygen-precovered Cu(111) and Cu2O(111) surfaces was studied with combined in situ near-ambient-pressure scanning tunneling microscopy and X-ray photoelectron spectroscopy. Activation of methane at 300 K and “moderate pressures” was only observed on oxygen-precovered Cu(111) surfaces. Density functional theory calculations reveal that the lowest activation energy barrier of C–H on Cu(111) in the presence of chemisorbed oxygen is related to a two-active-site, four-centered mechanism, which stabilizes the required transition-state intermediate by dipole–dipole attraction of O–H and Cu–CH3 species. The C–H bond activation barriers on Cu2O(111) surfaces are large due to the weak stabilization of H and CH3 fragments. |
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ISSN: | 1520-6106 1520-5207 |
DOI: | 10.1021/acs.jpcb.7b06956 |