Cooperative Redox Transitions Drive Electrocatalysis of the Oxygen Evolution Reaction on Cobalt–Iron Core–Shell Nanoparticles
| Autor: | Lisa Royer, Antoine Bonnefont, Tristan Asset, Benjamin Rotonnelli, Juan-Jesús Velasco-Vélez, Steven Holdcroft, Simon Hettler, Raul Arenal, Benoit Pichon, Elena Savinova |
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| Přispěvatelé: | Centre International de Recherche aux Frontières de la Chimie (France), Helmholtz-Zentrum Berlin for Materials and Energy, Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), Gobierno de Aragón, Diputación General de Aragón, European Commission |
| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | ACS Catalysis. 13:280-286 |
| ISSN: | 2155-5435 |
| Popis: | Transition metal oxides are promising materials for the development of cost-effective catalysts for the oxygen evolution reaction (OER) in alkaline media. Understanding the catalysts’ transformations occurring during the harsh oxidative conditions of the OER remains a bottleneck for the development of stable and active catalysts. Here, we studied redox transformations of core–shell Fe3O4@CoFe2O4 oxide nanoparticles over a wide range of potentials by using operando near-edge X-ray absorption fine structure (NEXAFS) spectroscopy in total electron yield (TEY) detection mode. The analysis of the NEXAFS spectra reveals that the Fe3O4 core strongly affects the surface chemistry of the CoFe2O4 shell under the OER conditions. The spinel structure of the particles with Co (II) in the shell is preserved at potentials as high as 1.8 V vs RHE, at which Co (II) is expected to be oxidized into Co (III); whereas Fe (II) in the core is reversibly oxidized to Fe (III). Project financially supported by the Foundation for Frontier Research in chemistry. We thank the Helmholtz-Zentrum Berlin für Materialien und Energie for the allocation of synchrotron radiation beamtime and Fabrice Bournel and Jean Jacques Gallet for their help in the project. The authors would also like to thank the XRD platform of ICPEES and the TEM platform of IPCMS as well as V. Ramnarain for the HRTEM micrographs and B. Freis for the TEM micrographs. R.A. and S.H. acknowledge support from Spanish MICINN (PID2019-104739GB-100/AEI/10.13039/501100011033), Government of Aragon (projects DGA E13-20R) and from EU H2020 “ESTEEM3” (Grant number 823717) and Graphene Flagship (881603). |
| Databáze: | OpenAIRE |
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