Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 86: Heterogeneous catalysis I
O 86.1: Vortrag
Donnerstag, 17. März 2011, 16:30–16:45, WIL B122
First-Principles kinetic Monte Carlo Simulations of Ammonia Oxidation at RuO2(110): Selectivity vs. semi-local DFT — •Claudia Mangold1 and Karsten Reuter1,2 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin — 2Technische Universität München
Reaching a detailed mechanistic understanding of high selectivity in surface catalytic processes is one of the central goals in present-day catalysis research.
The Surface Science approach to this problem focuses on the investigation of well-defined model systems that reduce the complexity but still capture the relevant aspects.
In this respect, the almost 100% selectivity reported in detailed experiments for the oxidation of NH3 to NO at RuO2(110) [1] presents an ideal benchmark
for a quantitative theoretical analysis. To this end we perform detailed kinetic Monte Carlo simulations based on kinetic parameters derived from density-functional theory (DFT).
The obtained turnover frequency for molecular nitrogen is in rather good agreement with the experimental data. However, even with an extended set of elementary processes we
are not able to reproduce the experimental findings for the production of NO and therewith the selectivity. The central quantities that decisively determine the latter are the binding
energy of NO and the N diffusion barrier. Suspecting the approximate energetics obtained with the employed semi-local DFT functional as reason for the discrepancy, we recalculate
the kinetic parameters with different functionals and discuss the resulting effects in the kMC simulations.
Y. Wang et al., J. Phys. Chem. B 109 (2005) 7883.