Tailoring the Oxygen Evolution Activity and Stability Using Defect Chemistry

Scholz, Julius; Risch, Marcel; Wartner, Garlef; Luderer, Christoph; Roddatis, Vladimir; Jooss, Christian

doi:10.3390/catal7050139

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Tailoring the Oxygen Evolution Activity and Stability Using Defect Chemistry

by

Julius Scholz

¹,

Marcel Risch

¹

,

Garlef Wartner

^1,2,

Christoph Luderer

¹,

Vladimir Roddatis

¹

and

Christian Jooss

^1,*

¹

Institute of Materials Physics, University of Goettingen, Friedrich-Hund Platz 1, 37077 Goettingen, Germany

²

Division of Fuel Cells, NEXT Energy, EWE-Forschungszentrum für Energietechnologie, e.V., Carl-von-Ossietzky-Straße 15, 26129 Oldenburg, Germany

^*

Author to whom correspondence should be addressed.

Catalysts 2017, 7(5), 139; https://doi.org/10.3390/catal7050139

Submission received: 6 March 2017 / Revised: 21 April 2017 / Accepted: 26 April 2017 / Published: 5 May 2017

(This article belongs to the Special Issue (Photo)Electrochemistry of Perovskites)

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Abstract

Improving the activity of catalysts for the oxygen evolution reaction (OER) requires a detailed understanding of the surface chemistry and structure to deduce structure-function relationships (descriptors) for fundamental insight. We chose epitaxial (100)-oriented La_0.6Sr_0.4Mn_1−δO₃ (LSMO) thin films as a model system with high electrochemical activity comparable to (110)-oriented IrO₂ to investigate the effect of Mn off-stoichiometry on both catalytic activity and stability. Extensive structural characterization was performed by microscopic and spectroscopic methods before and after electrochemical characterization using rotating ring-disk studies. Stoichiometric LSMO had the highest activity, while both Mn deficiency and excess reduced the catalytic activity. Furthermore, all samples preserved the crystal structure up to the very surface. Mn excess improved the long-term activity, and we hypothesize that excess Mn stabilizes the surface chemistry during catalysis. Our data show that the defect chemistry should be considered when designing catalysts with enhanced activity and rugged stability.

Keywords: oxygen evolution reaction; manganite; rotating-ring disk electrode; TEM; structural control

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MDPI and ACS Style

Scholz, J.; Risch, M.; Wartner, G.; Luderer, C.; Roddatis, V.; Jooss, C. Tailoring the Oxygen Evolution Activity and Stability Using Defect Chemistry. Catalysts 2017, 7, 139. https://doi.org/10.3390/catal7050139

AMA Style

Scholz J, Risch M, Wartner G, Luderer C, Roddatis V, Jooss C. Tailoring the Oxygen Evolution Activity and Stability Using Defect Chemistry. Catalysts. 2017; 7(5):139. https://doi.org/10.3390/catal7050139

Chicago/Turabian Style

Scholz, Julius, Marcel Risch, Garlef Wartner, Christoph Luderer, Vladimir Roddatis, and Christian Jooss. 2017. "Tailoring the Oxygen Evolution Activity and Stability Using Defect Chemistry" Catalysts 7, no. 5: 139. https://doi.org/10.3390/catal7050139

APA Style

Scholz, J., Risch, M., Wartner, G., Luderer, C., Roddatis, V., & Jooss, C. (2017). Tailoring the Oxygen Evolution Activity and Stability Using Defect Chemistry. Catalysts, 7(5), 139. https://doi.org/10.3390/catal7050139

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Tailoring the Oxygen Evolution Activity and Stability Using Defect Chemistry

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