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Mechanistic Explanation of the pH Dependence and Onset Potentials for Hydrocarbon Products from Electrochemical Reduction of CO on Cu (111)

Xiao, Hai and Cheng, Tao and Goddard, William A., III and Sundararaman, Ravishankar (2016) Mechanistic Explanation of the pH Dependence and Onset Potentials for Hydrocarbon Products from Electrochemical Reduction of CO on Cu (111). Journal of the American Chemical Society, 138 (2). pp. 483-486. ISSN 0002-7863. https://resolver.caltech.edu/CaltechAUTHORS:20160111-095847659

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Abstract

Energy and environmental concerns demand development of more efficient and selective electrodes for electrochemical reduction of CO_2 to form fuels and chemicals. Since Cu is the only pure metal exhibiting reduction to form hydrocarbon chemicals, we focus here on the Cu (111) electrode. We present a methodology for density functional theory calculations to obtain accurate onset electrochemical potentials with explicit constant electrochemical potential and pH effects using implicit solvation. We predict the atomistic mechanisms underlying electrochemical reduction of CO, finding that (1) at acidic pH, the C_1 pathway proceeds through COH to CHOH to form CH_4 while C_2 (C_3) pathways are kinetically blocked; (2) at neutral pH, the C_1 and C_2 (C_3) pathways share the COH common intermediate, where the branch to C–C coupling is realized by a novel CO–COH pathway; and (3) at high pH, early C–C coupling through adsorbed CO dimerization dominates, suppressing the C1 pathways by kinetics, thereby boosting selectivity for multi-carbon products.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/jacs.5b11390DOIArticle
http://pubs.acs.org/doi/10.1021/jacs.5b11390PublisherArticle
http://pubs.acs.org/doi/suppl/10.1021/jacs.5b11390PublisherSupporting Information
ORCID:
AuthorORCID
Xiao, Hai0000-0001-9399-1584
Cheng, Tao0000-0003-4830-177X
Goddard, William A., III0000-0003-0097-5716
Sundararaman, Ravishankar0000-0002-0625-4592
Additional Information:© 2015 American Chemical Society. ACS AuthorChoice - This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes. Received: October 30, 2015. Publication Date (Web): December 30, 2015. This work was supported by the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub, supported through the Office of Science of the U.S. Department of Energy under Award No. DE-SC0004993. We are grateful to Dr. Robert J. Nielsen, Dr. Manny Soriaga, and Mr. Yufeng Huang for helpful discussions. The computations were carried out on computing resources Zwicky (Caltech) and NERSC. The authors declare no competing financial interest.
Group:JCAP
Funders:
Funding AgencyGrant Number
Department of Energy (DOE)DE-SC0004993
Other Numbering System:
Other Numbering System NameOther Numbering System ID
WAG1201
Issue or Number:2
Record Number:CaltechAUTHORS:20160111-095847659
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20160111-095847659
Official Citation:Mechanistic Explanation of the pH Dependence and Onset Potentials for Hydrocarbon Products from Electrochemical Reduction of CO on Cu (111) Hai Xiao, Tao Cheng, William A. Goddard III, and Ravishankar Sundararaman Journal of the American Chemical Society 2016 138 (2), 483-486 DOI: 10.1021/jacs.5b11390
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:63536
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:13 Jan 2016 00:26
Last Modified:21 Feb 2020 17:20

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