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Catalytic Oxidation of CO on a Curved Pt(111) Surface: Simultaneous Ignition at All Facets Through a Transient CO-O Complex

preprint
submitted on 16.03.2020 and posted on 18.03.2020 by Fernando Garcia-Martinez, Carlos Garc´ıa-Fern´andez, Juan Pablo Simonovi, Adrian Hunt, Andrew Walter, Iradwikanari Waluyo, Florian Bertram, Lindsay R. Merte, Mikhail Shipilin, Sebastian Pfaff, Sara Blomberg, Johan Zetterberg, Johan Gustafson, Edvin Lundgren, Daniel S´anchez-Portal, Frederik Schiller, Enrique ortega
We combine PLIF and NAP-XPS to investigate the CO oxidation reaction at vicinal Pt(111) surfaces in the millibar regime, using a curved sample. We find that the catalytic activation of Pt occurs in all vicinal planes simultaneously,
irrespectively of the reaction parameters. The systematic analysis of chemical species across the entire curved surface provides the clues for this surprising behavior. As the surface CO concentration decreases when approaching ignition, minor amounts of oxygen build up at both steps and (111) terraces. First-principles theory indicates that the latter is forming a CO-Pt-O complex that binds CO molecules to terraces strongly, leveling its adsorption energy to that of low-coordinated steps, and explaining why CO abruptly desorbs at the same temperature along the di erent crystal facets that make up the curved Pt surface.

Funding

Ministry of Science and Technology of Spain

History

Email Address of Submitting Author

enrique.ortega@ehu.es

Institution

University of the Basque Country

Country

Spain

ORCID For Submitting Author

0000-0002-6643-806X

Declaration of Conflict of Interest

No conflict of interest

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