CO-CO coupling on Cu facets: Coverage, strain and field effects

Robert B. Sandberg, Joseph H. Montoya, Karen Chan, Jens K. Nørskov*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

We present a DFT study on the effect of coverage, strain, and electric field on CO-CO coupling energetics on Cu (100), (111), and (211). Our calculations indicate that CO-CO coupling is facile on all three facets in the presence of a cation-induced electric field in the Helmholtz plane, with the lowest barrier on Cu(100). The CO dimerization pathway is therefore expected to play a role in C2 formation at potentials negative of the Cu potential of zero charge, corresponding to CO2/CO reduction conditions at high pH. Both increased *CO coverage and tensile strain further improve C-C coupling energetics on Cu (111) and (211). Since CO dimerization is facile on all 3 Cu facets, subsequent surface hydrogenation steps may also play an important role in determining the overall activity towards C2 products. Adsorption of *CO, *H, and *OH on the 3 facets were investigated with a Pourbaix analysis. The (211) facet has the largest propensity to co-adsorb *CO and *H, which would favor surface hydrogenation following CO dimerization.

Original languageEnglish
JournalSurface Science
Volume654
Pages (from-to)56-62
ISSN0039-6028
DOIs
Publication statusPublished - 2016
Externally publishedYes

Keywords

  • C-C coupling
  • CO dimerization
  • CO reduction
  • Electrocatalysis

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