SKM 2023 – scientific programme
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O: Fachverband Oberflächenphysik
O 78: Heterogeneous Catalysis and Surface Dynamics II
O 78.6: Talk
Thursday, March 30, 2023, 11:45–12:00, TRE Phy
Studing of rate-limiting steps on CO2 reduction on ZnO/Cu(111) — •Sina Dortaj1,2 and Sebastian Matera1,2 — 1Fritz Haber Institute of the Max Planck Society, Berlin, Germany — 2Institute for Mathematics, Freie Universität, Berlin, Germany
To simulate the chemical kinetics of heterogeneous catalysts, the kinetic Monte Carlo (kMC) method is a common choice as it allows estimating turnover frequencies and coverages with a tunable accuracy. This advantage comes at much higher computational costs compared to classical kinetic approaches, in addition to stochastic noise on the simulation results. Thus, local sensitivity analysis to determine the rate-limiting step becomes cumbersome. Additionally, rate constants often carry some sizeable uncertainty due to the intrinsic approximations in quantum chemical methods or the noise in experimental data used to determine reaction barriers that make the use of just local methods obscure. We address both problems, high costs, and parameter uncertainties, by a novel global sensitivity analysis based on the Cramér von Mises distance and a Quasi-Monte Carlo sampling of the space of rate constants. While applicable to any model, our approach is particularly suited for the use of kMC and other Monte Carlo models. We demonstrate the approach on the CO2 reduction on ZnO/Cu(111) catalysts identifying the key atomic scale factors controlling activity and selectivity.