Berlin 2015 – scientific programme
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O: Fachverband Oberflächenphysik
O 6: Catalysis
O 6.10: Talk
Monday, March 16, 2015, 13:00–13:15, MA 043
First Principles kinetic Monte Carlo simulations of competitive CO and NO Oxidation on Pd(100) — •Juan Manuel Lorenzi1, Sebastian Matera1,2, and Karsten Reuter1 — 1Technische Universität München — 2Freie Universität Berlin
Lean-burn automotive emissions are characterized by an increased NOx content. A crucial step for the effective operation of NOx storage reduction (NSR) catalysts is to oxidize excess NO into NO2. In this context, interest shifts to understanding the oxidation properties of typically employed Pt-group catalysts under the simultaneous exposure to CO, NO and O2. We assess this for the Pd(100) model catalyst surface with first-principles kinetic Monte Carlo (1p-kMC) simulations that are based on an extensive set of density-functional theory derived rate constants. For gas-phase conditions representative for the oxidative mode of NSR (600 K, 1 atm O2, 10−3 atm NO) we obtain a NO oxidation activity of Pd(100) that is comparable to the one obtained previously for the (√5× √5)R27∘ surface oxide on Pd(100) [1]. Intriguingly, already corresponding small amounts of NO in the gas-mixture lead to qualitative changes in the CO oxidation properties. Particularly for oxygen-rich feeds the O coverage is substantially reduced, suggesting an increased resistance against oxide formation. [1] J. Jelic, K. Reuter, and R. Meyer, Chem. Cat. Chem. 2, 658 (2010).