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Approaching 100% Selectivity at Low Potential on Ag for Electrochemical CO₂ Reduction to CO Using a Surface Additive

Buckley, Aya K. and Cheng, Tao and Oh, Myoung Hwan and Su, Gregory M. and Garrison, Jennifer and Utan, Sean W. and Zhu, Chenhui and Toste, F. Dean and Goddard, William A., III and Toma, Francesca M. (2021) Approaching 100% Selectivity at Low Potential on Ag for Electrochemical CO₂ Reduction to CO Using a Surface Additive. ACS Catalysis, 11 (15). pp. 9034-9042. ISSN 2155-5435. doi:10.1021/acscatal.1c00830.

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We report the discovery of a quaternary ammonium surface additive for CO₂ reduction on Ag surfaces that changes the Faradaic efficiency for CO from 25% on Ag foil to 97%, while increasing the current density for CO production by a factor of 9 from 0.14 to 1.21 mA/cm² and reducing the current density for H₂ production by a factor of 440 from 0.44 to 0.001 mA/cm². Using ReaxFF reactive molecular dynamics, we find that the surface additive with the highest selectivity, dihexadecyldimethylammonium bromide, promotes substantial population of CO₂ near the Ag surface along with sufficient H₂O to activate the CO₂. While a critical number of water molecules is required in the reduction of CO₂ to CO, the trend in selectivity strongly correlates with the availability of CO₂ molecules. We demonstrate that the ordering of the cationic modifiers plays a significant role around the active site, thus determining reaction selectivity. The dramatic improvement by addition of a simple surface additive suggests an additional strategy in electrocatalysis.

Item Type:Article
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URLURL TypeDescription Information
Cheng, Tao0000-0003-4830-177X
Toste, F. Dean0000-0001-8018-2198
Goddard, William A., III0000-0003-0097-5716
Toma, Francesca M.0000-0003-2332-0798
Alternate Title:Approaching 100% Selectivity at Low Potential on Ag for Electrochemical CO2 Reduction to CO Using a Surface Additive
Additional Information:© 2021 The Authors. Published by American Chemical Society. Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) Received: February 23, 2021; Revised: June 15, 2021; Published: July 8, 2021. This material is based upon work performed 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. This research used beamline 7.3.3 of the Advanced Light Source, which is a DOE Office of Science User Facility under contract no. DE-AC02-05CH11231. Dr. Michelle Lee is acknowledged for helpful discussions. Author Contributions: A.K.B. and T.C. contributed equally. A.K.B., F.D.T., and F.M.T. conceptualized the project. A.K.B., J.G., and S.W.U carried out the experiments, and T.C. carried out the theoretical calculations. M.H.O. helped with data interpretation. C.Z. collected scattering data. G.M.S. and C.Z. analyzed and interpreted scattering data. F.D.T. and F.M.T. supervised the experimental portion and W.A.G. the theoretical portion of the project. A.K.B., T.C., W.A.G., and F.M.T wrote the original manuscript. All authors proofread, commented on, and approved the final manuscript for submission. The authors declare no competing financial interest.
Funding AgencyGrant Number
Department of Energy (DOE)DE-SC0004993
Department of Energy (DOE)DE-AC02-05CH11231
Subject Keywords:electrochemical CO₂ reduction; surface additives; interfaces; silver; molecular dynamics
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Issue or Number:15
Record Number:CaltechAUTHORS:20210716-164306725
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Official Citation:Approaching 100% Selectivity at Low Potential on Ag for Electrochemical CO2 Reduction to CO Using a Surface Additive. Aya K. Buckley, Tao Cheng, Myoung Hwan Oh, Gregory M. Su, Jennifer Garrison, Sean W. Utan, Chenhui Zhu, F. Dean Toste, William A. Goddard, and Francesca M. Toma. ACS Catalysis 2021 11 (15), 9034-9042; DOI: 10.1021/acscatal.1c00830
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:109873
Deposited By: Donna Wrublewski
Deposited On:16 Jul 2021 17:32
Last Modified:16 Nov 2021 19:38

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