Operando Identification of the Reversible Skin Layer on Co3O4as a Three-Dimensional Reaction Zone for Oxygen Evolution

Wiegmann T, Pacheco I, Reikowski F, Stettner J, Qiu C, Bouvier M, Bertram M, Faisal F, Brummel O, Libuda J, Drnec J, Allongue P, Maroun F, Magnussen OM (2022)

Publication Type: Journal article

Publication year: 2022

Journal

Pages Range: 3256-3268

DOI: 10.1021/acscatal.1c05169

Abstract

Co oxides and oxyhydroxides have been studied extensively in the past as promising electrocatalysts for the oxygen evolution reaction (OER) in neutral to alkaline media. Earlier studies showed the formation of an ultrathin CoOx(OH)y skin layer on Co3O4 at potentials above 1.15 V vs reversible hydrogen electrode (RHE), but the precise influence of this skin layer on the OER reactivity is still under debate. We present here a systematic study of epitaxial spinel-type Co3O4 films with defined (111) orientation, prepared on different substrates by electrodeposition or physical vapor deposition. The OER overpotential of these samples may vary up to 120 mV, corresponding to two orders of magnitude differences in current density, which cannot be accounted for by differences in the electrochemically active surface area. We demonstrate by a careful analysis of operando surface X-ray diffraction measurements that these differences are clearly correlated with the average thickness of the skin layer. The OER reactivity increases with the amount of formed skin layer, indicating that the entire three-dimensional skin layer is an OER-active interphase. Furthermore, a scaling relationship between the reaction centers in the skin layer and the OER activity is established. It suggests that two lattice sites are involved in the OER mechanism.

Authors with CRIS profile

Involved external institutions

École Polytechnique - Université Paris-Saclay France (FR) Christian-Albrechts-Universität zu Kiel Germany (DE) European Synchrotron Radiation Facility (ESRF) France (FR)

How to cite

APA:

Wiegmann, T., Pacheco, I., Reikowski, F., Stettner, J., Qiu, C., Bouvier, M.,... Magnussen, O.M. (2022). Operando Identification of the Reversible Skin Layer on Co3O4as a Three-Dimensional Reaction Zone for Oxygen Evolution. ACS Catalysis, 3256-3268. https://dx.doi.org/10.1021/acscatal.1c05169

MLA:

Wiegmann, Tim, et al. "Operando Identification of the Reversible Skin Layer on Co3O4as a Three-Dimensional Reaction Zone for Oxygen Evolution." ACS Catalysis (2022): 3256-3268.

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