Jinzhen Huang^1*, Natasha Hales^1*, Adam H. Clark^2*, Nur Sena Yüzbasi^3*, Camelia Nicoleta Borca^2*, Thomas Huthwelker^2*, Thomas J. Schmidt^1,4*, Emiliana Fabbri^1*

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 CoO_x and CeO₂ during oxygen evolution reaction, Materials Cloud Archive 2023.157 (2023), doi: 10.24435/materialscloud:yh-sq.

Description

CeO₂ greatly enhances the electrocatalytic oxygen evolution reaction (OER) activity of CoO_x, 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 CoO_x/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 CoO_x introduces significant modifications in the Co and O species at the CoO_x 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 CoO_x/CeO₂ composites electrodes.

Materials Cloud sections using this data

Files

File name	Size	Description
Raw data for CoOx CeO2 project.xlsx MD5md5:a80b1a69892473a93ba2503a555e731d	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

Keywords

Oxygen evolution reaction Co redox Co oxidation Operando XAS CeO2