Regensburg 2010 – scientific programme
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O: Fachverband Oberflächenphysik
O 4: Heterogeneous catalysis I
O 4.1: Talk
Monday, March 22, 2010, 11:15–11:30, H33
First-Principles statistical mechanics simulations of catalytic oxidation of ammonia at RuO2(110) — •Claudia Mangold1 and Karsten Reuter1,2 — 1Fritz-Haber-Institut, Berlin (Germany) — 2Technische Universität München (Germany)
RuO2(110) has evolved into a frequently studied model oxide surface, with appealing catalytic properties for a range of reactions. Recent experiments by Wang et al. [1] determined an almost 100% selectivity for the oxidation of ammonia, adding this first step of the Ostwald process to the list. In order to understand the mechanistic details behind this high selectivity we perform first-principles statistical mechanics simulations, based on density-functional theory for a quantitative account of the surface energetics. The atomistic thermodynamics phase diagram, constructed for a constrained equilibrium with the NH3 and O2 gas phase, points at a prominent role of the coordinatively unsaturated sites offered by the surface. First kinetic Monte Carlo simulations concentrate on the kinetics at these sites and reveal severe diffusion limitations at the nanostructured RuO2(110) surface.
[1] Wang et al., J. Phys. Chem. B 109 (2005) 7883.