Nonthermalized Precursor-Mediated Dissociative Chemisorption at High Catalysis Temperatures.

Autor: Moiraghi R; Instituto de Investigaciones en Fisicoquimica de Córdoba, CONICET, Universidad Nacional de Córdoba, Haya de la Torre s/n, X5000HUA Córdoba, Argentina., Lozano A; Department of Electrical Engineering and Computer Science, University of Lige, Alle de la Découverte 10, B-4000 Lige, Belgium., Peterson E; Department of Chemistry and W. M. Keck Foundation Laboratory of Materials Science, Tufts University, 62 Talbot Avenue, Medford, Massachusetts 02155, United States., Utz A; Department of Chemistry and W. M. Keck Foundation Laboratory of Materials Science, Tufts University, 62 Talbot Avenue, Medford, Massachusetts 02155, United States., Dong W; Université de Lyon, CNRS, Ecole Normale Supérieure de Lyon, Université Lyon 1, Laboratoire de Chimie, UMR 5182, 46, Allée d'Itallie, 69364 Lyon Cedex 07, France.; College of Chemistry and Chemical Engineering, Hunan University, 410082 Changsha, China., Busnengo HF; Grupo de Fisicoquímica en Interfases y Nanoestructuras, Instituto de Física Rosario and Universidad Nacional de Rosario, Bv. 27 de Febrero 210 bis, 2000 Rosario, Argentina.
Jazyk: angličtina
Zdroj: The journal of physical chemistry letters [J Phys Chem Lett] 2020 Mar 19; Vol. 11 (6), pp. 2211-2218. Date of Electronic Publication: 2020 Mar 05.
DOI: 10.1021/acs.jpclett.0c00260
Abstrakt: Quasiclassical trajectory calculations and vibrational-state-selected beam-surface measurements of CH 4 chemisorption on Ir(111) reveal a nonthermal, hot-molecule mechanism for C-H bond activation. Low-energy vibrationally excited molecules become trapped in the physisorption well and react before vibrational and translational energies accommodate the surface. The reaction probability is strongly surface-temperature-dependent and arises from the pivotal role of Ir atom thermal motion. In reactive trajectories, the mean outward Ir atom displacement largely exceeds that of the transition-state geometry obtained through a full geometry optimization. The study also highlights a new way for (temporary) surface defects to impact high-temperature heterogeneous catalytic reactivity. Instead of reactants diffusing to and competing for geometrically localized lower barrier sites, transient, thermally activated surface atom displacements deliver low-barrier surface reaction geometries to the physisorbed reactants.
Databáze: MEDLINE
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