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Journal articles
Achilles' heel of iron-based catalysts during oxygen reduction in acidic medium
Chang Hyuck Choi
1
Hyung-Kyu Lim
2
Min Wook Chung
1
Gajeon Chon
1
Nastaran Ranjbar Sahraie
3
Abdulrahman Altin
4
Moulay Tahar Sougrati
3
Lorenzo Stievano
3
Hyun Seok Oh
5
Eun-Soo Park
5
Fang Luo
6
Peter Strasser
6
Goran Dražić
7
Karl Mayrhofer
8
Hyungjun Kim
2
Frederic Jaouen
3
Chang Hyuck Choi 1
Author Employer institution : Gwangju Institute of Science and Technology
Hyung-Kyu Lim 2
Author
Min Wook Chung 1
Author
Gajeon Chon 1
Author
Nastaran Ranjbar Sahraie 3
Author
Abdulrahman Altin 4
Author
Moulay Tahar Sougrati 3
Mail :
Author IdHAL : m-sougrati
Lorenzo Stievano 3
Mail : Site :
Author IdHAL : loroik ResearcherId : http://www.researcherid.com/rid/B-7801-2010 ORCID : https://orcid.org/0000-0001-8548-0231
1
GIST - Gwangju Institute of Science and Technology (South Korea)
2
KAIST - Korea Advanced Institute of Science and Technology (291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea - South Korea)
3
ICGM ICMMM - Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (Bâtiment 15 - CC003 Place Eugène Bataillon - 34095 Montpellier cedex 5 - France)
- ENSCM - Ecole Nationale Supérieure de Chimie de Montpellier (8 Rue de l'Ecole Normale 34296 Montpellier Cedex 5 - France)
- CNRS - Centre National de la Recherche Scientifique : UMR5253 (France)
- UM - Université de Montpellier (163 rue Auguste Broussonnet - 34090 Montpellier - France)
- UM1 - Université Montpellier 1 (5, boulevard Henri IV - CS 19044 - 34967 Montpellier cedex - France)
- UM2 - Université Montpellier 2 - Sciences et Techniques (Place Eugène Bataillon - 34095 Montpellier cedex 5 - France)
4
Max-Planck-Gesellschaft (Jägerstrasse, 10-11, D-10117 Berlin - Germany)
5
SNU - Seoul National University [Seoul] (1 Gwanak-ro, Gwanak-gu, Seoul 151-742 - South Korea)
6
TUB - Technische Universität Berlin (Straße des 17. Juni 135 10623 Berlin - Germany)
7
National Institute of Chemistry (Hajdrihova 19
SI-1000 Ljubljana - Slovenia)
8
IEK-11 - Helmholtz Institute Erlangen Nürnberg for Renewable Energy (91058 Erlangen, Germany - Germany)
- Forschungszentrum Jülich GmbH (Wilhelm-Johnen-Straße, 52428 Jülich - Germany)
Abstract : For catalyzing dioxygen reduction, iron-nitrogen-carbon (Fe-N-C) materials are today the best candidates to replace platinum in proton-exchange membrane fuel cell (PEMFC) cathodes. Despite tremendous progress in their activity and site-structure understanding, improved durability is critically needed but challenged by insufficient understanding of their degradation mechanisms during operation. Here, we show that FeNxCy moieties in a representative Fe-N-C catalyst are structurally stable but electrochemically unstable when exposed in acidic medium to H2O2, the main oxygen reduction reaction (ORR) byproduct. We reveal that exposure to H2O2 leaves iron-based catalytic sites untouched but decreases their turnover frequency (TOF) via oxidation of the carbon surface, leading to weakened O2-binding on iron-based sites. Their TOF is recovered upon electrochemical reduction of the carbon surface, demonstrating the proposed deactivation mechanism. Our results reveal for the first time a hitherto unsuspected key deactivation mechanism during ORR in acidic medium. This study identifies the N-doped carbon surface as Achilles' heel during ORR catalysis in PEMFCs. Observed in acidic but not in alkaline electrolyte, these insights suggest that durable Fe-N-C catalysts are within reach for PEMFCs if rational strategies minimizing the amount of H2O2 or reactive oxygen species (ROS) produced during ORR are developed.
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https://hal.archives-ouvertes.fr/hal-01887695
Contributor : Frederic Jaouen <>
Submitted on : Thursday, October 4, 2018 - 1:33:11 PM
Last modification on : Monday, September 2, 2019 - 6:28:03 PM
Contributor : Frederic Jaouen <>
Submitted on : Thursday, October 4, 2018 - 1:33:11 PM
Last modification on : Monday, September 2, 2019 - 6:28:03 PM
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Identifiers
- HAL Id : hal-01887695, version 1
- DOI : 10.1039/C8EE01855C
Collections
CNRS | INC-CNRS | CHIMIE | UNIV-MONTPELLIER | ICG
Citation
Chang Hyuck Choi, Hyung-Kyu Lim, Min Wook Chung, Gajeon Chon, Nastaran Ranjbar Sahraie, et al.. Achilles' heel of iron-based catalysts during oxygen reduction in acidic medium. Energy & Environmental Science, Royal Society of Chemistry, 2018, 11 (11), pp.3176-3182. ⟨10.1039/C8EE01855C⟩. ⟨hal-01887695⟩
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