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O: Fachverband Oberflächenphysik

O 57: Surface Chemical Reactions and Heterogeneous Catalysis II

O 57.3: Vortrag

Donnerstag, 29. März 2007, 16:15–16:30, H38

CO oxidation on RuO₂(110): Temperature programmed reaction spectra from first-principles kMC simulations — •Michael Rieger, Jutta Rogal, and Karsten Reuter — Fritz-Haber-Institut, Faradayweg 4-6, D-14195 Berlin, Germany

The catalytic oxidation of CO over the RuO₂(110) surface has become a frequently studied model system, for which detailed data from steady-state activity measurements and ex-situ experiments is available. The steady-state activity of this surface was recently investigated by first-principles kinetic Monte Carlo (kMC) simulations [1], yielding very good agreement with experimental results. Using the same setup, and in particular, the same ab initio microscopic parameters, i.e. elementary processes (including desorption, diffusion and reaction events) and process rates based on density-functional theory (DFT) energetics, we now also reproduce detailed temperature programmed desorption (TPD) and reaction (TPR) data for this system [2]. We focus in particular on the experimentally found dependence of the CO₂ yield on the surface coverage, which could not be explained within a simple mean-field picture. Analyzing our simulation results, we can rationalize the observed non-intuitive dependence as the result of a coverage dependent interplay of different possible reaction processes taking place at the surface.

[1] K. Reuter, D. Frenkel, and M. Scheffler, Phys. Rev. Lett. 93, 116105 (2004); K. Reuter and M. Scheffler, Phys. Rev. B 73, 045433 (2006).

[2] S. Wendt, M. Knapp, and H. Over, J. Am. Chem. Soc. 126, 1537 (2004).