Dresden 2020 – scientific programme

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O: Fachverband Oberflächenphysik

O 67: Solid-Liquid Interfaces III: OER, ORR, CO2RR, etc.

O 67.11: Talk

Wednesday, March 18, 2020, 13:15–13:30, WIL C107

A refined view on broken scaling relations for electrochemical CO₂ reduction on transition metal carbides — •Haobo Li and Karsten Reuter — Chair for Theoretical Chemistry, TU Munich, Germany

The electrochemical reduction of CO₂ (CO2RR) is a promising approach to generate chemical energy carriers from renewable electricity. Transition metal carbides (TMCs) are a promising non-noble material class to catalyze this reaction, with e.g. Mo₂C recently reported to convert CO₂ into CH₄ at low overpotentials [1]. Here, we further assess the proposition that this performance results from a break of scaling relations known to limit CO2RR on transition metals (TMs) and their alloys [2]. Using density-functional theory, we systematically compute the adsorption energies of key reaction intermediates at multiple adsorption sites offered at low-index surfaces of molybdenum carbides of varying stoichiometry. The obtained data base provides a refined view, with certain scaling relations indeed broken, but others maintained. We can rationalize these findings by the simultaneous presence of metal and carbon active sites at the surface of TMC catalysts and the concomitant stabilization of varying adsorption modes. With this understanding we revisit mechanistic CO2RR models established for TMs and explore routes to optimize CO2RR for TMCs.

[1] S.K. Kim et al., ACS Catal. 6, 2003 (2016).

[2] R. Michalsky et al., J. Phys. Chem. C 118, 13026 (2014).