Deciphering Iron‐Dependent Activity in Oxygen Evolution Catalyzed by Nickel–Iron Layered Double Hydroxide. (11th March 2020)

• Record Type: Journal Article
• Authors: Lee, Seunghwa; Bai, Lichen; Hu, Xile
• Is Part Of: Angewandte Chemie. Volume 132:Number 21(2020)
• Page Start: 8149
• Page End: 8154
• Publication Date: 2020-03-11
• Subjects: Aktive Zentren -- Elektrokatalyse -- Nickeleisenoxyhydroxid -- Raman-Spektroskopie -- Sauerstoffentwicklungsreaktion; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201915803
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: 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. Abstract : Eisen versus Nickel : Turnover‐Frequenzen (TOFs) von Ni‐ und Fe‐Zentren bei der Sauerstoffentwicklungsreaktion, die von einer Serie geschichteter Ni‐ und NiFe‐Doppelhydroxide katalysiert wird, wurden bestimmt. Zudem wurden die Auswirkungen struktureller Fehlordnung des NiOOH‐Gitters aufgeklärt.