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Operando tracking the interactions between CoOx and CeO₂ during oxygen evolution reaction

Jinzhen Huang1*, Natasha Hales1*, Adam H. Clark2*, Nur Sena Yüzbasi3*, Camelia Nicoleta Borca2*, Thomas Huthwelker2*, Thomas J. Schmidt1,4*, Emiliana Fabbri1*

1 Electrochemistry Laboratory, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland

2 Photon Science Division, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland

3 Laboratory for High Performance Ceramics, Empa - Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland

4 Institute for Physical Molecular Sciences, ETH Zürich, CH-8093 Zürich, Switzerland

* Corresponding authors emails: jinzhen.huang@psi.ch, natasha.hales@psi.ch, adam.clark@psi.ch, Sena.Yuezbasi@empa.ch, camelia.borca@psi.ch, thomas.huthwelker@psi.ch, thomasjustus.schmidt@psi.ch, emiliana.fabbri@psi.ch
DOI10.24435/materialscloud:yh-sq [version v1]

Publication date: Oct 17, 2023

How to cite this record

Jinzhen Huang, Natasha Hales, Adam H. Clark, Nur Sena Yüzbasi, Camelia Nicoleta Borca, Thomas Huthwelker, Thomas J. Schmidt, Emiliana Fabbri, Operando tracking the interactions between CoOx and CeO₂ during oxygen evolution reaction, Materials Cloud Archive 2023.157 (2023), https://doi.org/10.24435/materialscloud:yh-sq


CeO₂ greatly enhances the electrocatalytic oxygen evolution reaction (OER) activity of CoOx, though the enhancement mechanism beyond this synergy is yet to be understood. Here, operando hard X-ray adsorption spectroscopy (hXAS) is applied to monitor the Co K edge and Ce L₃ edge in CoOx/CeO₂ to shed light on the evolution of the Co and Ce oxidation states during OER. In addition, ex situ soft XAS (sXAS) characterizations provide information on the irreversible surface-specific transformations of the Co L₃ edge as well as of the O K edge. Combining the operando and ex situ spectroscopic characterizations with comprehensive electrochemical analyses, we confirm CeO₂ is not the active center for the OER. However, coupling CeO₂ with CoOx introduces significant modifications in the Co and O species at the CoOx surface and alters the flat band potential (Efb), leading to more favorable Co oxidation state transformations during OER and possibly modifying the preferential reaction pathway. This work establishes the connections between electronic structures, Co oxidation state and the OER reaction mechanism for CoOx/CeO₂ composites electrodes.

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File name Size Description
Raw data for CoOx CeO2 project.xlsx
5.4 MiB The files contains the raw data for the figures in the main text (including electrochemical measurement, hXAS and sXAS charaterizations).


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External references

Journal reference
J Huang,* N. Hales,[a] A. H. Clark, N. S. Yüzbasi, C. N. Borca, T. Huthwelker, T. J. Schmidt and E. Fabbri*, submitted (2023) doi:submitted


Oxygen evolution reaction Co redox Co oxidation Operando XAS CeO2

Version history:

2023.157 (version v1) [This version] Oct 17, 2023 DOI10.24435/materialscloud:yh-sq