Dresden 2009 – scientific programme

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O: Fachverband Oberflächenphysik

O 45: Heterogeneous catalysis

O 45.3: Talk

Thursday, March 26, 2009, 11:00–11:15, SCH A215

From electrons to reactive flow: Coupling first-principles kinetic Monte Carlo with continuum level simulations — •Sebastian Matera and Karsten Reuter — Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin

First-principles kinetic Monte Carlo (kMC) simulations have evolved into an important tool in the modeling of heterogeneous catalytic processes. The success of the approach relies on the accurate treatment of two central aspects for the reactive surface chemistry: A first-principles description of the involved elementary processes and an evaluation of their statistical interplay that fully accounts for the correlations, fluctuations and spatial distributions of the chemicals at the catalyst surface. Particularly for technologically more relevant environments, i.e. ambient pressures and elevated temperatures with concomitant higher product formation rates, a third aspect in form of the heat and mass flow in the system becomes increasingly important. We investigate these effects by coupling first-principles kMC simulations self-consistently with continuum level simulations for the gas and solid phase transport, considering a stagnation point flow geometry as a model for recent in situ measurements over single-crystal model catalysts. Applying our method to the CO oxidation over RuO₂(110) [1], we demonstrate how the build-up of temperature and pressure gradients over the active surface influence the observed catalytic activity and surface composition.

[1] K. Reuter and M. Scheffler, Phys. Rev. B 73, 045433 (2006).