Oxygen Reduction Reaction in Alkaline Media Causes Iron Leaching from Fe-N-C Electrocatalysts
Ku YP, Ehelebe K, Hutzler A, Bierling M, Boehm T, Zitolo A, Vorokhta M, Bibent N, Speck FD, Seeberger D, Khalakhan I, Mayrhofer KJJ, Thiele S, Jaouen F, Cherevko S (2022)
Publication Type: Journal article
Publication year: 2022
Journal
Book Volume: 144
Pages Range: 9753-9763
Journal Issue: 22
DOI: 10.1021/jacs.2c02088
Abstract
The electrochemical activity of modern Fe-N-C electrocatalysts in alkaline media is on par with that of platinum. For successful application in fuel cells (FCs), however, also high durability and longevity must be demonstrated. Currently, a limited understanding of degradation pathways, especially under operando conditions, hinders the design and synthesis of simultaneously active and stable Fe-N-C electrocatalysts. In this work, using a gas diffusion electrode half-cell coupled with inductively coupled plasma mass spectrometry setup, Fe dissolution is studied under conditions close to those in FCs, that is, with a porous catalyst layer (CL) and at current densities up to -125 mA.cm(-2). Varying the rate of the oxygen reduction reaction (ORR), we show a remarkable linear correlation between the Faradaic charge passed through the electrode and the amount of Fe dissolved from the electrode. This finding is rationalized assuming that oxygen reduction and Fe dissolution reactions are interlinked, likely through a common intermediate formed during the Fe redox transitions in Fe species involved in the ORR, such as FeNxCy and Fe3C@N-C. Moreover, such a linear correlation allows the application of a simple metric-S-number-to report the material's stability. Hence, in the current work, a powerful tool for a more applied stability screening of different electrocatalysts is introduced, which allows on the one hand fast performance investigations under more realistic conditions, and on the other hand a more advanced mechanistic understanding of Fe-N-C degradation in CLs.
Authors with CRIS profile
Involved external institutions
Forschungszentrum Jülich / Research Centre Jülich (FZJ)
Germany (DE)
Univerzita Karlova v Praze / Charles University in Prague
Czech Republic (CZ)
University of Montpellier / Université Montpellier
France (FR)
Synchrotron SOLEIL
France (FR)
Germany (DE)
Univerzita Karlova v Praze / Charles University in Prague
Czech Republic (CZ)
University of Montpellier / Université Montpellier
France (FR)
Synchrotron SOLEIL
France (FR)
How to cite
APA:
Ku, Y.-P., Ehelebe, K., Hutzler, A., Bierling, M., Boehm, T., Zitolo, A.,... Cherevko, S. (2022). Oxygen Reduction Reaction in Alkaline Media Causes Iron Leaching from Fe-N-C Electrocatalysts. Journal of the American Chemical Society, 144(22), 9753-9763. https://dx.doi.org/10.1021/jacs.2c02088
MLA:
Ku, Yu-Ping, et al. "Oxygen Reduction Reaction in Alkaline Media Causes Iron Leaching from Fe-N-C Electrocatalysts." Journal of the American Chemical Society 144.22 (2022): 9753-9763.
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