# Regensburg 2004 – wissenschaftliches Programm

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# O: Oberflächenphysik

## O 20: Oberflächenreaktionen I

### O 20.4: Vortrag

### Dienstag, 9. März 2004, 12:00–12:15, H45

**CO oxidation at RuO**_{2}**(110) studied by first-principles kinetic Monte-Carlo simulations** — •Karsten Reuter^{1,2}, Daan Frenkel^{2}, and Matthias Scheffler^{1} — ^{1}Fritz-Haber-Institut, Berlin — ^{2}AMOLF, Amsterdam

A quantitative modeling of catalytic activity requires
a high accuracy in the description of each of the
manifold of involved elementary processes, as well as a
correct statistical mechanics treatment of the interplay
between them. We attempt such a modeling by first-principles
kinetic Monte-Carlo simulations, i.e. using rates
derived from density-functional theory as input. Modeling
the CO oxidation over RuO_{2}(110) we obtain a full
(*T*,*p*_{O2},*p*_{CO}) turnover frequency diagram,
which agrees with available experimental data. The surface
configurations actuating catalysis are found to be strongly
influenced by kinetic effects, most prominently under gas
phase conditions where the system is close to a surface
phase transition. The highest steady-state turnover rates
are obtained for the resulting phase coexistence at the
surface, which enables specific reaction mechanisms
that do not operate at other temperature and pressure
conditions including ultra-high vacuum.