SurfaceScience21 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 20: Poster Session II: Heterogeneous catalysis II
O 20.4: Poster
Montag, 1. März 2021, 13:30–15:30, P
Performance and predictions of kinetic models for MgO-catalyzed ethanol conversion to butadiene — •Astrid Boje1, William E. Taifan2, Henrik Ström1, Tomáš Bučko3,4, Jonas Baltrusaitis2, and Anders Hellman1 — 1Chalmers University of Technology, Göteborg, Sweden. — 2Lehigh University, Bethlehem, USA. — 3Comenius University in Bratislava, Bratislava, Slovak Republic. — 4Slovak Academy of Sciences, Bratislava, Slovak Republic.
Formation of 1,3-butadiene from ethanol is a sustainable alternative to conventional synthesis; however, selectivity is challenging and there is significant sensitivity to catalyst composition and conditions. We employ a combination of first-principles-informed energetic span and microkinetic models to interrogate the kinetic behavior of this system on a model MgO catalyst, demonstrating the utility and limitations of both perspectives. The microkinetic model was developed based on the extensive DFT mechanism of Taifan et al. [1], comprising several possible pathways. Both models allow quantification of rate-determining states and turnover, with the microkinetic model characterizing kinetic limitations due to coverage and adsorption/desorption effects. The dominance of the pathways varied with temperature. We considered the impact of uncertainty in the free energy landscape on kinetic predictions by sampling from a correlated error model, finding that the microkinetic model was less robust but both models predicted similar median outcomes. The two models thus provide valuable and complementary insights into the operation of a complex, selectivity-limited process. [1] Taifan, W. E., et al., J. Catal. 346, 78 (2017).