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Operando X‐Ray Absorption Spectroscopy Shows Iron Oxidation Is Concurrent with Oxygen Evolution in Cobalt–Iron (Oxy)hydroxide Electrocatalysts
Author(s) -
Enman Lisa J.,
Stevens Michaela Burke,
Dahan Meir Haim,
Nellist Michael R.,
Toroker Maytal Caspary,
Boettcher Shan W.
Publication year - 2018
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201808818
Subject(s) - cobalt , catalysis , oxygen evolution , chemistry , oxygen , nickel , inorganic chemistry , cobalt hydroxide , x ray absorption spectroscopy , absorption spectroscopy , hydroxide , absorption (acoustics) , spectroscopy , photochemistry , materials science , electrochemistry , organic chemistry , physics , electrode , quantum mechanics , composite material
Abstract Iron cations are essential for the high activity of nickel and cobalt‐based (oxy)hydroxides for the oxygen evolution reaction, but the role of iron in the catalytic mechanism remains under active investigation. Operando X‐ray absorption spectroscopy and density functional theory calculations are used to demonstrate partial Fe oxidation and a shortening of the Fe−O bond length during oxygen evolution on Co(Fe)O x H y . Cobalt oxidation during oxygen evolution is only observed in the absence of iron. These results demonstrate a different mechanism for water oxidation in the presence and absence of iron and support the hypothesis that oxidized iron species are involved in water‐oxidation catalysis on Co(Fe)O x H y .