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Structure and composition of Cu(hkl) surfaces exposed to O_2 and emersed from alkaline solutions: Prelude to UHV-EC studies of CO_2 reduction at well-defined copper catalysts

Baricuatro, Jack H. and Ehlers, Charles B. and Cummins, Kyle D. and Soriaga, Manuel P. and Stickney, John L. and Kim, Youn-Geun (2014) Structure and composition of Cu(hkl) surfaces exposed to O_2 and emersed from alkaline solutions: Prelude to UHV-EC studies of CO_2 reduction at well-defined copper catalysts. Journal of Electroanalytical Chemistry, 716 . pp. 101-105. ISSN 1572-6657. https://resolver.caltech.edu/CaltechAUTHORS:20140312-092635775

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Abstract

The ability of copper electrodes to catalyze the reduction of carbon dioxide better than any single-metal material is now well known. However, it is also an established fact that copper is an efficient scavenger of dry oxygen. Hence, the initiation of the CO_2 reduction reaction at copper must contend with the presence of surface oxides spontaneously formed when the metal is exposed to ambient air. In this regard, the interfacial structures and compositions of Cu(1 0 0), Cu(1 1 0) and Cu(1 1 1), before and after exposure to gaseous oxygen and emersion from in mildly alkaline media (pH 8 and 10), were characterized by a combination of electrochemistry and electron spectroscopy (low-energy electron diffraction and Auger electron spectroscopy). The affinity of the low-index copper planes to oxygen gas was found to decrease in the order Cu(1 1 0) > Cu(1 0 0) > Cu(1 1 1). The same reactivity trend was exhibited by the electrodes emersed from alkaline K_2SO_4 solution. The initial stages of the anodic oxidation of copper, prior to formation of bulk oxides, span a wide potential window that is pH-sensitive; within this precursory region, submonolayer coverages of oxygen tended to form surface domains with long-range order. At potentials far below the anodic-oxidation region (E < −0.90 V), the surface compositions and structures of Cu(hkl) are expected to mimic those of zerovalent copper. These results may bear significant implications in the generation as well as identification of surface-bound intermediates that define the electrocatalytic selectivity of copper towards the reduction of molecular species such as CO_2 and CO in alkaline media.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1016/j.jelechem.2013.10.001DOIArticle
http://www.sciencedirect.com/science/article/pii/S1572665713004384PublisherArticle
ORCID:
AuthorORCID
Soriaga, Manuel P.0000-0002-0077-6226
Kim, Youn-Geun0000-0002-5936-6520
Additional Information:© 2013 Elsevier B.V. Available online 10 October 2013. Special Issue in Honour of Kingo Itaya. This material is based upon work performed by the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub, as follows: The surface electrochemistry-spectroscopy analysis and interpretation were supported through the Office of Science of the U.S. Department of Energy under Award No. DE-SC0004993; the preparation and initial surface characterization of the copper tri-crystal electrode were supported by the National Science Foundation, Division of Materials Research (DMR-1006747) (JLS).
Group:JCAP
Funders:
Funding AgencyGrant Number
Department of Energy (DOE)DE-SC0004993
NSFDMR-1006747
Subject Keywords:Surface studies of tri-faceted copper; Copper single-crystal electrodes; Ultrahigh Vacuum-Electrochemistry (UHV-EC); Air oxidation of Cu(hkl) surfaces; Copper emersed from alkaline solutions
Record Number:CaltechAUTHORS:20140312-092635775
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20140312-092635775
Official Citation:Jack H. Baricuatro, Charles B. Ehlers, Kyle D. Cummins, Manuel P. Soriaga, John L. Stickney, Youn-Geun Kim, Structure and composition of Cu(hkl) surfaces exposed to O2 and emersed from alkaline solutions: Prelude to UHV-EC studies of CO2 reduction at well-defined copper catalysts, Journal of Electroanalytical Chemistry, Volume 716, 1 March 2014, Pages 101-105, ISSN 1572-6657, http://dx.doi.org/10.1016/j.jelechem.2013.10.001. (http://www.sciencedirect.com/science/article/pii/S1572665713004384)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:44272
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:12 Mar 2014 16:42
Last Modified:03 Oct 2019 06:16

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