SurfaceScience21 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 8: Poster Session I: Solid-liquid interfaces: Structure, spectroscopy
O 8.8: Poster
Montag, 1. März 2021, 10:30–12:30, P
How surface oxides determine the activity of Mo2C electrocatalysts — •Christoph Griesser1, Haobo Li2, Eva-Maria Wernig1, Daniel Winkler1, David Egger2,3, Christoph Scheurer2,3, Karsten Reuter2,3, and Julia Kunze Liebhäuser1 — 1Department of Physical Chemistry, Universität Innsbruck, Austria — 2Chair of Theoretical Chemistry and Catalysis Research Center, Technische Universität München, Germany — 3Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany
Transition metal (TM) compounds are widely applicable as materials in heterogeneous catalysis, due to their compositional and structural diversity. TM carbide compounds are praised as electrocatalysts for the CO2 reduction reaction (CO2RR), due to a possible break of key adsorption energy scaling relations, predicted by density-functional theory studies. Mo2C was classified as highly suitable for the CO2RR in an active-site computational screening study. Here we assess the activity of hexagonal Mo2C towards the CO2RR in aqueous electrolyte by a multimethod experiment and theory approach. We find, that an ultrathin oxide film persists at the surface of this catalyst material and completely suppresses any CO2RR activity. The one monolayer thin oxide films are stable down to -1.9 VSHE, and exclusively the hydrogen reduction reaction is found to take place. This points to the necessity of considering the true interface, forming under operando conditions, in computational screenings for catalyst materials. Preliminary experiments performed under protection of Mo2C from ambient air in non-aqueous electrolyte indeed reveal CO2RR activity.