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Anomalous Behavior of Ru for Catalytic Oxidation: A Theoretical Study of the Catalytic Reaction CO+12O2→CO2

C. Stampfl and M. Scheffler

  • Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin-Dahlem, Germany

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Phys. Rev. Lett. 78, 1500 – Published 24 February, 1997

DOI: https://doi.org/10.1103/PhysRevLett.78.1500

Abstract

Recent experiments revealed an anomalous dependence of carbon monoxide oxidation at Ru(0001) on oxygen pressure and a particularly high reaction rate. Below we report density functional theory calculations of the energetics and reaction pathways of the speculated mechanism. We will show that the exceptionally high rate is actuated by a weakly but nevertheless well bound (1×1)-oxygen adsorbate layer. Furthermore, it is found that reactions via scattering of gas-phase CO at the oxygen covered surface may play an important role. Our analysis reveals, however, that reactions via adsorbed CO molecules (the so-called Langmuir-Hinshelwood mechanism) dominate.

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References (22)

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  21. For our estimate we use the frequency of impinging CO molecules per surface Ru atom of ν=7.5×106s−1 which corresponds to a CO gas phase pressure of 16 torr.
  22. This value is obtained as the reaction energy of CO+12O2→CO2 in vacuum, minus the energy gained on adsorption of 12O2 and CO onto the surface.

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Phys. Rev. Lett. 78, 1500– Published 24 February, 1997
  • Received 15 April 1996

© 1997 American Physical Society

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