Journal Article

PUBDB-2022-01347

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Operando Identification of the Reversible Skin Layer on Co$_3$O$_4$ as a Three-Dimensional Reaction Zone for Oxygen Evolution

Wiegmann, T.Extern* ; Pacheco, I. ; Reikowski, F.Extern* ; Stettner, J.Extern* ; Qiu, C.Extern* ; Bouvier, M.Extern* ; Bertram, M.Extern* ; Faisal, F. ; Brummel, O.Extern* ; Libuda, J.Extern* ; Drnec, J.Extern* ; Allongue, P. (Corresponding author) ; Maroun, F. (Corresponding author)Extern* ; Magnussen, O. (Corresponding author)Extern*

2022
ACS Washington, DC

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Please use a persistent id in citations: doi:10.1021/acscatal.1c05169  doi:10.3204/PUBDB-2022-01347

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 CoO$_x$(OH)$_y$ skin layer on Co$_3$O$_4$ 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 Co$_3$O$_4$ 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.

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Contributing Institute(s):

1. DOOR-User (DOOR ; HAS-User)
2. Uni Kiel (UKiel)

Research Program(s):

1. 6G3 - PETRA III (DESY) (POF4-6G3) (POF4-6G3)

Experiment(s):

1. PETRA Beamline P23 (PETRA III)

Appears in the scientific report 2022

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Essential Science Indicators ; IF >= 10 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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