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Title: Mechanism of CO 2 Reduction at Copper Surfaces: Pathways to C 2 Products

Abstract

On the basis of constraints from reported experimental observations and density functional theory simulations, in this paper we propose a mechanism for the reduction of CO 2 to C 2 products on copper electrodes. To model the effects of an applied potential bias on the reactions, calculations are carried out with a variable, fractional number of electrons on the unit cell, which is optimized so that the Fermi level matches the actual chemical potential of electrons (i.e., the applied bias); an implicit electrolyte model allows for compensation of the surface charge so that neutrality is maintained in the overall simulation cell. Our mechanism explains the presence of the seven C 2 species that have been detected in the reaction, as well as other notable experimental observations. Furthermore, our results shed light on the difference in activities toward C 2 products between the (100) and (111) facets of copper. Finally, we compare our methodologies and findings with those in other recent mechanistic studies of the copper-catalyzed CO 2 reduction reaction.

Authors:
 [1]; ORCiD logo [2]; ORCiD logo [3]
  1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Joint Center for Artificial Photosynthesis
  2. Univ. of California, Berkeley, CA (United States). Dept. of Chemical and Biomolecular Engineering
  3. Univ. of California, Berkeley, CA (United States). Dept. of Chemistry
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1464161
Grant/Contract Number:  
AC02-05CH11231; SC0004993
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
ACS Catalysis
Additional Journal Information:
Journal Volume: 8; Journal Issue: 2; Journal ID: ISSN 2155-5435
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; artificial photosynthesis; DFT; electrocatalysis; ethanol; ethylene; mechanisms

Citation Formats

Garza, Alejandro J., Bell, Alexis T., and Head-Gordon, Martin. Mechanism of CO2 Reduction at Copper Surfaces: Pathways to C2 Products. United States: N. p., 2018. Web. doi:10.1021/acscatal.7b03477.
Garza, Alejandro J., Bell, Alexis T., & Head-Gordon, Martin. Mechanism of CO2 Reduction at Copper Surfaces: Pathways to C2 Products. United States. doi:10.1021/acscatal.7b03477.
Garza, Alejandro J., Bell, Alexis T., and Head-Gordon, Martin. Thu . "Mechanism of CO2 Reduction at Copper Surfaces: Pathways to C2 Products". United States. doi:10.1021/acscatal.7b03477. https://www.osti.gov/servlets/purl/1464161.
@article{osti_1464161,
title = {Mechanism of CO2 Reduction at Copper Surfaces: Pathways to C2 Products},
author = {Garza, Alejandro J. and Bell, Alexis T. and Head-Gordon, Martin},
abstractNote = {On the basis of constraints from reported experimental observations and density functional theory simulations, in this paper we propose a mechanism for the reduction of CO2 to C2 products on copper electrodes. To model the effects of an applied potential bias on the reactions, calculations are carried out with a variable, fractional number of electrons on the unit cell, which is optimized so that the Fermi level matches the actual chemical potential of electrons (i.e., the applied bias); an implicit electrolyte model allows for compensation of the surface charge so that neutrality is maintained in the overall simulation cell. Our mechanism explains the presence of the seven C2 species that have been detected in the reaction, as well as other notable experimental observations. Furthermore, our results shed light on the difference in activities toward C2 products between the (100) and (111) facets of copper. Finally, we compare our methodologies and findings with those in other recent mechanistic studies of the copper-catalyzed CO2 reduction reaction.},
doi = {10.1021/acscatal.7b03477},
journal = {ACS Catalysis},
issn = {2155-5435},
number = 2,
volume = 8,
place = {United States},
year = {2018},
month = {1}
}

Journal Article:
Free Publicly Available Full Text
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Cited by: 43 works
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Figures / Tables:

Figure 1: Figure 1:: Proposed mechanism for the reduction of CO to C2 products at high potentials on Cu(100). Calculated free energies (eV) are the numbers parallel to reaction arrows, where ∆G values at U = 0 V using the CHE appear in standard font (steps involving H+ + e can bemore » corrected to U = −1 V by subtracting 1 eV). ∆G values at U = −1 V using the CEP (at pH = 7) appear in bold font. The seven C2 products of CO2 reduction on copper are highlighted in green. Calculated free energy barriers (eV) are provided for the critical reductive step from intermediate 3 to either 4a or 4b that determines selectivity between the pathway to ethylene (purple) and ethanol (blue).« less

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Works referencing / citing this record:

Structure‐Sensitivity and Electrolyte Effects in CO 2 Electroreduction: From Model Studies to Applications
journal, June 2019

  • Sebastián‐Pascual, Paula; Mezzavilla, Stefano; Stephens, Ifan E. L.
  • ChemCatChem, Vol. 11, Issue 16
  • DOI: 10.1002/cctc.201900552

    Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.