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Free-Energy Barriers and Reaction Mechanisms for the Electrochemical Reduction of CO on the Cu(100) Surface, Including Multiple Layers of Explicit Solvent at pH 0

Cheng, Tao and Xiao, Hai and Goddard, William A., III (2015) Free-Energy Barriers and Reaction Mechanisms for the Electrochemical Reduction of CO on the Cu(100) Surface, Including Multiple Layers of Explicit Solvent at pH 0. Journal of Physical Chemistry Letters, 6 (23). pp. 4767-4773. ISSN 1948-7185. https://resolver.caltech.edu/CaltechAUTHORS:20151123-110728006

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Abstract

The great interest in the photochemical reduction from CO_2 to fuels and chemicals has focused attention on Cu because of its unique ability to catalyze formation of carbon-containing fuels and chemicals. A particular goal is to learn how to modify the Cu catalysts to enhance the production selectivity while reducing the energy requirements (overpotential). To enable such developments, we report here the free-energy reaction barriers and mechanistic pathways on the Cu(100) surface, which produces only CH_4 (not C_2H_4 or CH_3OH) in acid (pH 0). We predict a threshold potential for CH_4 formation of −0.52 V, which compares well to experiments at low pH, −0.45 to −0.50 V. These quantum molecular dynamics simulations included ∼5 layers of explicit water at the water/electrode interface using enhanced sampling methodology to obtain the free energies. We find that that chemisorbed hydroxyl-methylene (CH–OH) is the key intermediate determining the selectivity for methane over methanol.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/acs.jpclett.5b02247DOIArticle
http://pubs.acs.org/doi/10.1021/acs.jpclett.5b02247PublisherArticle
http://pubs.acs.org/doi/suppl/10.1021/acs.jpclett.5b02247PublisherSupplementary Information
ORCID:
AuthorORCID
Cheng, Tao0000-0003-4830-177X
Xiao, Hai0000-0001-9399-1584
Goddard, William A., III0000-0003-0097-5716
Additional Information:© 2015 American Chemical Society. 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 8, 2015; Accepted: November 12, 2015; Published: November 12, 2015. This work was initiated with support from National Science Foundation (CHE 1512759 and completed with support 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 DE-SC0004993. We thank Dr. Robert J. Nielsen, Dr. Manny Soriaga, and Ms. Yufeng Huang for helpful discussions. The authors declare no competing financial interest.
Group:JCAP
Funders:
Funding AgencyGrant Number
NSFCHE-1512759
Department of Energy (DOE)DE-SC0004993
Subject Keywords:interface; electrochemistry; CO2 reduction; quantum molecular dynamics; density functional theory; PBE; metadynamics; constrained molecular dynamics; free energy; green chemistry
Other Numbering System:
Other Numbering System NameOther Numbering System ID
WAG1145
Issue or Number:23
Record Number:CaltechAUTHORS:20151123-110728006
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20151123-110728006
Official Citation:Free-Energy Barriers and Reaction Mechanisms for the Electrochemical Reduction of CO on the Cu(100) Surface, Including Multiple Layers of Explicit Solvent at pH 0 Tao Cheng, Hai Xiao, and William A. Goddard, III The Journal of Physical Chemistry Letters 2015 6 (23), 4767-4773 DOI: 10.1021/acs.jpclett.5b02247
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:62330
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:23 Nov 2015 19:14
Last Modified:03 Oct 2019 09:17

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