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Time-resolved oxidation state changes are key to elucidating the bifunctionality of perovskite catalysts for oxygen evolution and reduction

Casey E. Beall1, Emiliana Fabbri1*, Adam H. Clark1, Vivian Meier1,2, Nur Sena Yüzbasi3, Benjamin H. Sjølin4, Ivano E. Castelli4*, Dino Aegerter1, Thomas Graule3, Thomas J. Schmidt1,2

1 Paul Scherrer Institute (PSI), 5232 Villigen PSI, Switzerland

2 Institute for Physical Molecular Science, ETH Zürich, 8093 Zürich, Switzerland

3 Empa, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland

4 Department of Energy Conversion and Storage, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark

* Corresponding authors emails: emiliana.fabbri@psi.ch, ivca@dtu.dk
DOI10.24435/materialscloud:bk-y8 [version v1]

Publication date: Jul 28, 2023

How to cite this record

Casey E. Beall, Emiliana Fabbri, Adam H. Clark, Vivian Meier, Nur Sena Yüzbasi, Benjamin H. Sjølin, Ivano E. Castelli, Dino Aegerter, Thomas Graule, Thomas J. Schmidt, Time-resolved oxidation state changes are key to elucidating the bifunctionality of perovskite catalysts for oxygen evolution and reduction, Materials Cloud Archive 2023.121 (2023), https://doi.org/10.24435/materialscloud:bk-y8


In a unified regenerative fuel cell (URFC) or reversible fuel cell the oxygen bifunctional catalyst must switch reversibly between the oxygen reduction reaction (ORR), fuel cell mode, and the oxygen evolution reaction (OER), electrolyzer mode. However, it is often unclear what effect alternating between ORR and OER has on the electrochemical behavior and physiochemical properties of the catalyst. Herein, operando X-ray absorption spectroscopy (XAS) is utilized to monitor the continuous and dynamic evolution of the Co, Mn, and Fe oxidation states of perovskite catalysts Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) and La0.4Sr0.6MnO3-δ (LSM), while the potential is oscillated between reducing and oxidizing potentials with cyclic voltammetry. The results reveal the importance of investigating bifunctional catalysts by alternating between fuel cell and electrolyzer operation and highlight the limitations and challenges of bifunctional catalysts. It is shown that the requirements for ORR and OER performance are divergent and that the oxidative potentials of OER are detrimental to ORR activity. These findings are used to give guidelines for future bifunctional catalyst design. Additionally, it is demonstrated how sunlight can be used to reactivate the ORR activity of LSM after rigorous cycling.

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File name Size Description
2.7 KiB Conductivity Measurements
1.8 MiB Electrochemistry
20.8 KiB XRD
909.2 MiB XAS
485 Bytes Read me text file


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ORR OER alkaline Experimental SNSF

Version history:

2023.121 (version v1) [This version] Jul 28, 2023 DOI10.24435/materialscloud:bk-y8