Title: Edge-Enhanced Oxygen Evolution Reactivity at Ultrathin, Au-Supported Fe₂O₃ Electrocatalysts

Abstract

Transition metal oxides have gained attention as promising oxygen evolution reaction (OER) electrocatalysts in alkaline electrolytes, but heterogeneities in typical catalyst samples often obscure key structure–property relationships that are essential for developing higher performance materials. Here, we have combined ultrahigh vacuum surface science techniques, electrochemical measurements, and density functional theory (DFT) to quantify structure-dependent OER activity in a series of well-defined electrocatalysts. We describe a direct correlation between the population of Fe edge-site atoms and the OER activity of ultrathin Fe₂O₃ nanostructures (~0.5 nm apparent height) grown on Au(111) substrates. Hydroxylated Fe atoms residing at edge-sites along the catalyst/support interface were spectroscopically identified as key reaction centers, and these Fe edge-site atoms were estimated to produce OER turnover frequencies approximately 150 times higher than that of Fe atoms on the catalyst surface at an applied potential of 1.8 V vs the reversible hydrogen electrode. Impressively, ultrathin Fe₂O₃/Au nanostructures with a high density of catalytically active Fe edge-site atoms outperformed an ultrathin IrO$$_x$$/Au catalyst at moderate overpotentials. DFT calculations revealed more favorable OER at edge sites along the Fe₂O₃/Au interface, with lower predicted overpotentials due to beneficial modification of intermediate binding. Our results demonstrate how a combination of surface science, electrochemistry, and computational modeling can be used to identify key structure–property relationships in a well-defined electrocatalytic system.

Authors:

Kauffman, Douglas R.  ^[1];

• Search DOE PAGES for author "Kauffman, Douglas R."
• Search DOE PAGES for ORCID "0000-0002-7855-3428"

Deng, Xingyi ^[2]; Sorescu, Dan C. ^[1]; Nguyen-Phan, Thuy-Duong  ^[2];

• Search DOE PAGES for author "Nguyen-Phan, Thuy-Duong"
• Search DOE PAGES for ORCID "0000-0002-6932-8851"

Wang, Congjun ^[2]; Marin, Chris M. ^[2]; Stavitski, Eli ^[3]; Waluyo, Iradwikanari  ^[3];

• Search DOE PAGES for author "Waluyo, Iradwikanari"
• Search DOE PAGES for ORCID "0000-0002-4046-9722"

Hunt, Adrian ^[3]

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+ Show Author Affiliations

1. National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)
2. National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Leidos Research Support Team, Pittsburgh, PA (United States)
3. Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source II (NSLS-II)

Publication Date:

Thu May 02 00:00:00 EDT 2019

Research Org.:

Brookhaven National Lab. (BNL), Upton, NY (United States); National Energy Technology Laboratory (NETL), Pittsburgh, PA, Morgantown, WV, and Albany, OR (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Fossil Energy (FE)

OSTI Identifier:

1543414

Alternate Identifier(s):

OSTI ID: 1569813

Report Number(s):

BNL-211909-2019-JAAM; NETL-PUB-22261
Journal ID: ISSN 2155-5435

Grant/Contract Number:  

SC0012704; 89243318CFE000003

Resource Type:

Accepted Manuscript

Journal Name:

ACS Catalysis

Additional Journal Information:

Journal Volume: 9; Journal Issue: 6; 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; oxygen evolution reaction; well-defined catalysts; density functional theory; electrocatalysis; scanning tunneling microscopy; surface science; electrochemistry; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY