Title: Correlating Oxidation State and Surface Area to Activity from Operando Studies of Copper CO Electroreduction Catalysts in a Gas-Fed Device

Abstract

Copyright © 2020 American Chemical Society. The rational design of high-performance electrocatalysts requires a detailed understanding of dynamic changes in catalyst properties, including oxidation states, surface area, and morphology under realistic working conditions. Oxide-derived Cu catalysts exhibit a remarkable selectivity toward multicarbon products for the electrochemical CO reduction reaction (CORR), but the exact role of the oxide remains elusive for explaining the performance enhancements. Here, we used operando X-ray absorption spectroscopy (XAS) coupled with simultaneous measurements of the catalyst activity and selectivity by gas chromatography (GC) to study the relationship between oxidation states of Cu-based catalysts and the activity for ethylene (C2H4) production in a CO gas-fed cell. By utilizing a custom-built XAS cell, oxidation states of Cu catalysts can be probed in device-relevant settings and under high current densities (>80 mA cm-2) for the CORR. By employing an electrochemical oxidation process, we found that the Cu oxidation states and specific ion species do not correlate with C2H4 production. The difference in the CORR activity is also investigated in relation to electrochemical surface area (ECSA) changes. While the hydrogen evolution reaction (HER) activity is positively correlated to the ECSA changes, the increased C2H4 activity is not proportional to the ECSA.more » Ex situ characterization from microscopic techniques suggests that the changes in the C2H4 activity and selectivity may arise from a morphological transformation that evolves into a more active structure. These comprehensive results give rise to the development of a cell regeneration method that can restore the performance of the Cu catalyst without cell disassembly. Our study establishes a basis for the rational design of highly active electrocatalysts for broad-range reactions in a gas-fed device.« less

Authors:

Lee, Soo Hong  ^[1];

• Search DOE PAGES for author "Lee, Soo Hong"
• Search DOE PAGES for ORCID "0000-0002-2734-9654"

Sullivan, Ian  ^[2];

• Search DOE PAGES for author "Sullivan, Ian"
• Search DOE PAGES for ORCID "0000-0003-0632-4607"

Larson, David M. ^[1]; Liu, Guiji ^[1]; Toma, Francesca M.  ^[1];

• Search DOE PAGES for author "Toma, Francesca M."
• Search DOE PAGES for ORCID "0000-0003-2332-0798"

Xiang, Chengxiang  ^[2];

• Search DOE PAGES for author "Xiang, Chengxiang"
• Search DOE PAGES for ORCID "0000-0002-1698-6754"

Drisdell, Walter S.  ^[1]

• Search DOE PAGES for author "Drisdell, Walter S."
• Search DOE PAGES for ORCID "0000-0002-8693-4562"

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+ Show Author Affiliations

1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
2. California Institute of Technology (CalTech), Pasadena, CA (United States)

Publication Date:

Thu Jun 25 00:00:00 EDT 2020

Research Org.:

Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division

OSTI Identifier:

1764521

Grant/Contract Number:  

AC02-05CH11231; AC02-76SF00515; SC0004993

Resource Type:

Accepted Manuscript

Journal Name:

ACS Catalysis

Additional Journal Information:

Journal Volume: 10; Journal Issue: 14; Journal ID: ISSN 2155-5435

Publisher:

American Chemical Society (ACS)

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; catalysts; electrochemical cells; oxidation; oxidation state; electrical properties