Promotion of CO Oxidation on Bimetallic Au−Ag(110) Surfaces: A Combined Microscopic and Theoretical Study
| Autor: | Chien Hong Lin, Jyh-Pin Chou, Ching-Ming Wei, Woei Wu Pai, Ching-Chang Kuo, Jian Der Lee |
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| Rok vydání: | 2009 |
| Předmět: |
Chemistry
Redox Surfaces Coatings and Films Electronic Optical and Magnetic Materials Catalysis law.invention Reaction rate General Energy Adsorption Computational chemistry law Atom Physical chemistry Density functional theory Physical and Theoretical Chemistry Scanning tunneling microscope Bimetallic strip |
| Zdroj: | The Journal of Physical Chemistry C. 113:13151-13159 |
| ISSN: | 1932-7455 1932-7447 |
| DOI: | 10.1021/jp811238w |
| Popis: | The clean-off reaction of AgO added rows by CO on Ag(110) and Au/Ag(110) bimetallic surfaces was studied by scanning tunneling microscopy (STM) and compared with density functional theory (DFT). This combined study of a model system illustrated the complexity of catalytic enhancement in bimetallic systems. By analyzing in situ time-lapsed STM image series, we found that CO oxidation on a Au-enriched Ag(110) surface leads to an exponential depletion of oxygen with time and a reaction rate that is synergistically enhanced by the presence of Au. First principles calculations indicate that the local atomic configuration around the active reaction sites at the chain ends and the preference of Au atom substitution into the subsurface second Ag layer are of critical importance. By calculating CO adsorption energies and reaction barriers for plausible reaction pathways, a detailed description of the CO oxidation reaction emerges. For the optimal reaction pathway, a large (∼0.09 eV) barrier reduction and a small b... |
| Databáze: | OpenAIRE |
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