Dresden 2006 – wissenschaftliches Programm

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O: Oberflächenphysik

O 28: Surface reactions II

O 28.3: Vortrag

Dienstag, 28. März 2006, 16:15–16:30, WIL C207

Analysis of the compensation effect observed in first-principles kinetic Monte Carlo simulations of heterogeneous catalysis — •Hakim Meskine, Karsten Reuter, and Matthias Scheffler — Fritz-Haber-Institut, Faradayweg 4-6, D-14195 Berlin, Germany

First-principles kinetic Monte Carlo (kMC) simulations for heterogeneous catalysis provide quantitative microscopic insight into the steady-state catalytic activity, fully accounting for the correlations, fluctuations and spatial distributions of the chemicals at the catalyst surface [1]. Density-functional theory is employed to accurately obtain the energetics of the manifold of relevant processes, while a correct statistical mechanics treatment of their interplay is taken care of by the kMC algorithm. In the application of this approach to the CO oxidation at a RuO₂(110) model catalyst, we compute the composition and structure of the surface in reactive environments ranging from ultra-high vacuum to technologically relevant conditions with pressures of the order of atmospheres and elevated temperatures. The catalytic activity is narrowly peaked in environments, where the surface kinetics builds a disordered and dynamic adsorbate composition at the surface. Our analysis shows that the strong process interplay makes this resulting optimum mix at the catalyst surface highly adaptive.

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