True Nature of the Transition-Metal Carbide/Liquid Interface Determines Its Reactivity

Christoph Griesser, Haobo Li, Eva Maria Wernig, Daniel Winkler, Niusha Shakibi Nia, Thomas Mairegger, Thomas Götsch, Thomas Schachinger, Andreas Steiger-Thirsfeld, Simon Penner, Dominik Wielend, David Egger, Christoph Scheurer, Karsten Reuter, Julia Kunze-Liebhäuser

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

Compound materials, such as transition-metal (TM) carbides, are anticipated to be effective electrocatalysts for the carbon dioxide reduction reaction (CO2RR) to useful chemicals. This expectation is nurtured by density functional theory (DFT) predictions of a break of key adsorption energy scaling relations that limit CO2RR at parent TMs. Here, we evaluate these prospects for hexagonal Mo2C in aqueous electrolytes in a multimethod experiment and theory approach. We find that surface oxide formation completely suppresses the CO2 activation. The oxides are stable down to potentials as low as -1.9 V versus the standard hydrogen electrode, and solely the hydrogen evolution reaction (HER) is found to be active. This generally points to the absolute imperative of recognizing the true interface establishing under operando conditions in computational screening of catalyst materials. When protected from ambient air and used in nonaqueous electrolyte, Mo2C indeed shows CO2RR activity.

Original languageEnglish
Pages (from-to)4920-4928
Number of pages9
JournalACS Catalysis
Volume11
Issue number8
DOIs
StatePublished - 16 Apr 2021

Keywords

  • HER
  • XPS
  • ab initio thermodynamics
  • electrocatalysis
  • electrochemical COreduction
  • solid/liquid interface
  • surface Pourbaix diagram
  • transition-metal carbides

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