Casey E. Beall¹, Emiliana Fabbri^1*, Adam H. Clark¹, Vivian Meier^1,2, Nur Sena Yüzbasi³, Thomas Graule³, Sayaka Takahashi⁴, Yuto Shirase⁴, Makoto Uchida⁴, Thomas J. Schmidt^1,2

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 Hydrogen and Fuel Cell Nanomaterials Center, University of Yamanashi, 400-0021, Kofu, Japan

* Corresponding authors emails: emiliana.fabbri@psi.ch

DOI10.24435/materialscloud:q7-74 [version v1]

Publication date: Jun 21, 2024

How to cite this record

Casey E. Beall, Emiliana Fabbri, Adam H. Clark, Vivian Meier, Nur Sena Yüzbasi, Thomas Graule, Sayaka Takahashi, Yuto Shirase, Makoto Uchida, Thomas J. Schmidt, Designing bifunctional perovskite catalysts for the oxygen reduction and evolution reactions, Materials Cloud Archive 2024.93 (2024), https://doi.org/10.24435/materialscloud:q7-74

Description

The development of unified regenerative fuel cells (URFC) necessitates an active and stable bifunctional oxygen electrocatalyst. The unique challenge of possessing high activity for both the oxygen reduction (ORR) and oxygen evolution (OER) reactions, while maintaining stability over a wide potential window impedes the design of bifunctional oxygen electrocatalysts. Herein, two design strategies are explored to optimize their performance. The first incorporates active sites for ORR and OER, Mn and Co, into a single perovskite structure, which is achieved with the perovskites Ba_0.5Sr_0.5Co_0.8Mn_0.2O_3-δ (BSCM) and La_0.5Ba_0.25Sr_0.25Co_0.5Mn_0.5O_3-δ (LBSCM). The second combines an active ORR perovskite catalyst (La_0.4Sr_0.6MnO_3-δ (LSM)) with an OER active perovskite catalyst (Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ (BSCF)) in a physical mixed composite (BSCF/LSM). The success of the two strategies is investigated by measuring the catalysts’ catalytic performance and response to alternating reducing and oxidizing potentials to mimic the dynamic conditions experienced during operation of URFCs. Additionally, the continuous, potentiodynamic change in Mn, Co, and Fe oxidation state during ORR and OER is elucidated with operando X-ray absorption spectroscopy (XAS) measurements, revealing key insights into the nature of the active sites. The results reveal important catalyst physiochemical properties and provide a guide for future research and design principles for bifunctional oxygen electrocatalysts.

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File name	Size	Description
READ ME.txt MD5md5:684c4a1af3f7ad0160fa8ccafd387387	415 Bytes	READ ME
Bifunctional Design Paper Archive.zip MD5md5:1ab3e34807fc1af7e8da267bbd223067	7.6 MiB	Raw data from the figures in the main text of the journal article. Data includes electrochemical data (RDE and single cell AEMWE and AEMFC tests) and operando XAS data.

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Keywords

ORR OER perovskite