Deciphering Iron‐Dependent Activity in Oxygen Evolution Catalyzed by Nickel–Iron Layered Double Hydroxide

Nickel iron oxyhydroxide is the benchmark catalyst for the oxygen evolution reaction (OER) in alkaline medium. Whereas the presence of Fe ions is essential to the high activity, the functions of Fe are currently under debate. Using oxygen isotope labeling and operando Raman spectroscopic experiments...

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Bibliographic Details
Published inAngewandte Chemie International Edition Vol. 59; no. 21; pp. 8072 - 8077
Main Authors Lee, Seunghwa, Bai, Lichen, Hu, Xile
Format Journal Article
LanguageEnglish
Published Germany Wiley Subscription Services, Inc 18.05.2020
EditionInternational ed. in English
Subjects
active sites
Catalysis
Catalysts
electrocatalysis
Hydroxides
Intermetallic compounds
Iron
Iron compounds
Nickel
Nickel compounds
Nickel iron
nickel iron oxyhydroxide
Oxygen
oxygen evolution reaction
Oxygen evolution reactions
Oxygen isotopes
Raman spectroscopy
Volcanoes
active sites
oxygen evolution reaction
Raman spectroscopy
electrocatalysis
nickel iron oxyhydroxide
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Summary:Nickel iron oxyhydroxide is the benchmark catalyst for the oxygen evolution reaction (OER) in alkaline medium. Whereas the presence of Fe ions is essential to the high activity, the functions of Fe are currently under debate. Using oxygen isotope labeling and operando Raman spectroscopic experiments, we obtain turnover frequencies (TOFs) of both Ni and Fe sites for a series of Ni and NiFe layered double hydroxides (LDHs), which are structurally defined samples of the corresponding oxyhydroxides. The Fe sites have TOFs 20–200 times higher than the Ni sites such that at an Fe content of 4.7 % and above the Fe sites dominate the catalysis. Higher Fe contents lead to larger structural disorder of the NiOOH host. A volcano‐type correlation was found between the TOFs of Fe sites and the structural disorder of NiOOH. Our work elucidates the origin of the Fe‐dependent activity of NiFe LDH, and suggests structural ordering as a strategy to improve OER catalysts. Iron versus nickel: Turnover frequencies (TOFs) of both Ni and Fe sites in the oxygen evolution reaction (OER) catalyzed by a series of Ni and NiFe layered double hydroxides (LDHs) have been determined. Effects of structural disorder of NiOOH lattice are revealed.
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ISSN:1433-7851
1521-3773
DOI:10.1002/anie.201915803