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Title: Observing the Electrochemical Oxidation of Co Metal at the Solid/Liquid Interface Using Ambient Pressure X-ray Photoelectron Spectroscopy

Abstract

Some rcent advances of ambient pressure X-ray photoelectron spectroscopy (AP-XPS) have enabled the chemical composition and the electrical potential profile at a liquid/electrode interface under electrochemical reaction conditions to be directly probed. In this work, we apply this operando technique to study the surface chemical composition evolution on a Co metal electrode in 0.1 M KOH aqueous solution under various electrical biases. It is found that an ~12.2 nm-thick layer of Co(OH) 2 forms at a potential of about -0.4 V Ag/AgCl, and upon increasing the anodic potential to about +0.4 V Ag/AgCl, this layer is partially oxidized into cobalt oxyhydroxide (CoOOH). A CoOOH/Co(OH) 2 mixture layer is formed on the top of the electrode surface. Finally, the oxidized surface layer can be reduced to Co0 at a cathodic potential of -1.35 VAg/Cl. Our observations indicate that the ultrathin layer containing cobalt oxyhydroxide is the active phase for oxygen evolution reaction (OER) on a Co electrode in an alkaline electrolyte, consistent with previous studies.

Authors:
 [1];  [2]; ORCiD logo [2];  [3];  [3];  [2];  [4];  [1]; ORCiD logo [1]
  1. Chinese Academy of Sciences (CAS), Beijing (China). Shanghai Inst. of Microsystem and Information Technology; Shanghai Tech Univ. (China). SChool of Physical Science and Technology
  2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source
  3. Chinese Academy of Sciences (CAS), Beijing (China). Shanghai Inst. of Microsystem and Information Technology
  4. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Science Division
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1408469
Grant/Contract Number:
AC02-05CH11231
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry
Additional Journal Information:
Journal Volume: 122; Journal Issue: 2; Journal ID: ISSN 1520-6106
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Han, Yong, Axnanda, Stephanus, Crumlin, Ethan J., Chang, Rui, Mao, Baohua, Hussain, Zahid, Ross, Philip N., Li, Yimin, and Liu, Zhi. Observing the Electrochemical Oxidation of Co Metal at the Solid/Liquid Interface Using Ambient Pressure X-ray Photoelectron Spectroscopy. United States: N. p., 2017. Web. doi:10.1021/acs.jpcb.7b05982.
Han, Yong, Axnanda, Stephanus, Crumlin, Ethan J., Chang, Rui, Mao, Baohua, Hussain, Zahid, Ross, Philip N., Li, Yimin, & Liu, Zhi. Observing the Electrochemical Oxidation of Co Metal at the Solid/Liquid Interface Using Ambient Pressure X-ray Photoelectron Spectroscopy. United States. doi:10.1021/acs.jpcb.7b05982.
Han, Yong, Axnanda, Stephanus, Crumlin, Ethan J., Chang, Rui, Mao, Baohua, Hussain, Zahid, Ross, Philip N., Li, Yimin, and Liu, Zhi. Mon . "Observing the Electrochemical Oxidation of Co Metal at the Solid/Liquid Interface Using Ambient Pressure X-ray Photoelectron Spectroscopy". United States. doi:10.1021/acs.jpcb.7b05982.
@article{osti_1408469,
title = {Observing the Electrochemical Oxidation of Co Metal at the Solid/Liquid Interface Using Ambient Pressure X-ray Photoelectron Spectroscopy},
author = {Han, Yong and Axnanda, Stephanus and Crumlin, Ethan J. and Chang, Rui and Mao, Baohua and Hussain, Zahid and Ross, Philip N. and Li, Yimin and Liu, Zhi},
abstractNote = {Some rcent advances of ambient pressure X-ray photoelectron spectroscopy (AP-XPS) have enabled the chemical composition and the electrical potential profile at a liquid/electrode interface under electrochemical reaction conditions to be directly probed. In this work, we apply this operando technique to study the surface chemical composition evolution on a Co metal electrode in 0.1 M KOH aqueous solution under various electrical biases. It is found that an ~12.2 nm-thick layer of Co(OH)2 forms at a potential of about -0.4 VAg/AgCl, and upon increasing the anodic potential to about +0.4 VAg/AgCl, this layer is partially oxidized into cobalt oxyhydroxide (CoOOH). A CoOOH/Co(OH)2 mixture layer is formed on the top of the electrode surface. Finally, the oxidized surface layer can be reduced to Co0 at a cathodic potential of -1.35 VAg/Cl. Our observations indicate that the ultrathin layer containing cobalt oxyhydroxide is the active phase for oxygen evolution reaction (OER) on a Co electrode in an alkaline electrolyte, consistent with previous studies.},
doi = {10.1021/acs.jpcb.7b05982},
journal = {Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry},
number = 2,
volume = 122,
place = {United States},
year = {Mon Aug 28 00:00:00 EDT 2017},
month = {Mon Aug 28 00:00:00 EDT 2017}
}

Journal Article:
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