Atomic-scale insights into surface reconstruction and transformation in Co-Cr spinel oxides during the oxygen evolution reaction

He B, Hosseini P, Priamushko T, Trost O, Budiyanto E, Bondue C, Schulwitz J, Kostka A, Tüysüz H, Muhler M, Cherevko S, Tschulik K, Li T (2025)

Publication Type: Journal article

Publication year: 2025

Journal

Nature Communications Nature Publishing Group: Nature Communications

Book Volume: 16

Article Number: 9895

Journal Issue: 1

DOI: 10.1038/s41467-025-65626-x

Abstract

Optimizing the activity and longevity of oxygen evolution reaction (OER) electrocatalysts requires an atomic-scale understanding of multiple reconstruction and transformation processes occurring in the surface and sub-surface regions of the electrocatalyst. Herein, a multimodal method combining X-ray absorption fine structure and photoemission spectroscopy, in situ Raman spectroscopy, transmission electron microscopy and atom probe tomography with electrochemical measurements is employed to unveil how the changes in oxidation states, atomic coordination, structure and composition on ~20 nm CoCr2O4 and Co2CrO4 spinel nanoparticle surfaces affect OER activity and stability in alkaline media. CoCr2O4 undergoes an activation process and subsequently retains high OER activity for extended durations. The activation of CoCr2O4 is induced by a steady and substantial Cr dissolution that facilitates bulk incorporation and intercalation of hydroxide ions, coupled with the highly reversible (CoTdII,Cr)(OH)2 ↔ (CoOctIII,Cr)OOH transformation, which enhances OER activity and stability. In comparison, a ~ 2 nm thick amorphous self-limiting Cr-based (oxy)hydroxide forms on Co2CrO4 upon cycling, contributing to OER activity. As OER proceeds, such Cr-based (oxy)hydroxide layers on Co2CrO4 are depleted from the surfaces, leading to deteriorating activity. Overall, this study demonstrates that continuous Cr dissolution triggers an intercalation-assisted (CoTdII,Cr)(OH)2 ↔ (CoOctIII,Cr)OOH transformation that can promote the OER activity and stability of Co-based spinels.

Involved external institutions

Ruhr-Universität Bochum (RUB) DE Germany (DE) Forschungszentrum Jülich / Research Centre Jülich (FZJ) DE Germany (DE) Max-Planck-Institut für Kohlenforschung (MPI KoFo) / Max Planck Institute for Coal Research DE Germany (DE) Max-Planck-Institut für Eisenforschung GmbH (MPIE) / Max Planck Institute for Iron Research DE Germany (DE)

How to cite

APA:

He, B., Hosseini, P., Priamushko, T., Trost, O., Budiyanto, E., Bondue, C.,... Li, T. (2025). Atomic-scale insights into surface reconstruction and transformation in Co-Cr spinel oxides during the oxygen evolution reaction. Nature Communications, 16(1). https://doi.org/10.1038/s41467-025-65626-x

MLA:

He, Biao, et al. "Atomic-scale insights into surface reconstruction and transformation in Co-Cr spinel oxides during the oxygen evolution reaction." Nature Communications 16.1 (2025).

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