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Title: Nature and Distribution of Stable Subsurface Oxygen in Copper Electrodes During Electrochemical CO 2 Reduction

Oxide-derived copper (OD-Cu) electrodes exhibit higher activity than pristine copper during the carbon dioxide reduction reaction (CO 2RR) and higher selectivity toward ethylene. The presence of residual subsurface oxygen in OD-Cu has been proposed to be responsible for such improvements, although its stability under the reductive CO 2RR conditions remains unclear. This work sheds light on the nature and stability of subsurface oxygen. Our spectroscopic results show that oxygen is primarily concentrated in an amorphous 1–2 nm thick layer within the Cu subsurface, confirming that subsurface oxygen is stable during CO 2RR for up to 1 h at –1.15 V vs RHE. Besides, it is associated with a high density of defects in the OD-Cu structure. In conclusion, we propose that both low coordination of the amorphous OD-Cu surface and the presence of subsurface oxygen that withdraws charge from the copper sp- and d-bands might selectively enhance the binding energy of CO.
Authors:
ORCiD logo [1] ;  [2] ;  [2] ;  [3] ; ORCiD logo [4] ; ORCiD logo [4] ; ORCiD logo [5] ;  [6] ;  [4] ; ORCiD logo [4]
  1. Stockholm Univ., Stockholm (Sweden); SLAC National Accelerator Lab., Menlo Park, CA (United States)
  2. LNESS Lab. and Dipartimento di Fisica, Como (Italy); Instituto Nazionale di Fisica Nucleare, Milano (Italy)
  3. Stockholm Univ., Stockholm (Sweden); SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States)
  4. Stockholm Univ., Stockholm (Sweden)
  5. Stanford Univ., Stanford, CA (United States)
  6. Technical Univ. of Denmark, Lyngby (Denmark)
Publication Date:
Grant/Contract Number:
AC02-76SF00515
Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. C
Additional Journal Information:
Journal Volume: 121; Journal Issue: 45; Journal ID: ISSN 1932-7447
Publisher:
American Chemical Society
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1463314

Cavalca, Filippo, Ferragut, Rafael, Aghion, Stefano, Eilert, André, Diaz-Morales, Oscar, Liu, Chang, Koh, Ai Leen, Hansen, Thomas W., Pettersson, Lars G. M., and Nilsson, Anders. Nature and Distribution of Stable Subsurface Oxygen in Copper Electrodes During Electrochemical CO2 Reduction. United States: N. p., Web. doi:10.1021/acs.jpcc.7b08278.
Cavalca, Filippo, Ferragut, Rafael, Aghion, Stefano, Eilert, André, Diaz-Morales, Oscar, Liu, Chang, Koh, Ai Leen, Hansen, Thomas W., Pettersson, Lars G. M., & Nilsson, Anders. Nature and Distribution of Stable Subsurface Oxygen in Copper Electrodes During Electrochemical CO2 Reduction. United States. doi:10.1021/acs.jpcc.7b08278.
Cavalca, Filippo, Ferragut, Rafael, Aghion, Stefano, Eilert, André, Diaz-Morales, Oscar, Liu, Chang, Koh, Ai Leen, Hansen, Thomas W., Pettersson, Lars G. M., and Nilsson, Anders. 2017. "Nature and Distribution of Stable Subsurface Oxygen in Copper Electrodes During Electrochemical CO2 Reduction". United States. doi:10.1021/acs.jpcc.7b08278. https://www.osti.gov/servlets/purl/1463314.
@article{osti_1463314,
title = {Nature and Distribution of Stable Subsurface Oxygen in Copper Electrodes During Electrochemical CO2 Reduction},
author = {Cavalca, Filippo and Ferragut, Rafael and Aghion, Stefano and Eilert, André and Diaz-Morales, Oscar and Liu, Chang and Koh, Ai Leen and Hansen, Thomas W. and Pettersson, Lars G. M. and Nilsson, Anders},
abstractNote = {Oxide-derived copper (OD-Cu) electrodes exhibit higher activity than pristine copper during the carbon dioxide reduction reaction (CO2RR) and higher selectivity toward ethylene. The presence of residual subsurface oxygen in OD-Cu has been proposed to be responsible for such improvements, although its stability under the reductive CO2RR conditions remains unclear. This work sheds light on the nature and stability of subsurface oxygen. Our spectroscopic results show that oxygen is primarily concentrated in an amorphous 1–2 nm thick layer within the Cu subsurface, confirming that subsurface oxygen is stable during CO2RR for up to 1 h at –1.15 V vs RHE. Besides, it is associated with a high density of defects in the OD-Cu structure. In conclusion, we propose that both low coordination of the amorphous OD-Cu surface and the presence of subsurface oxygen that withdraws charge from the copper sp- and d-bands might selectively enhance the binding energy of CO.},
doi = {10.1021/acs.jpcc.7b08278},
journal = {Journal of Physical Chemistry. C},
number = 45,
volume = 121,
place = {United States},
year = {2017},
month = {10}
}