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The Marriage of the FeN 4 Moiety and MXene Boosts Oxygen Reduction Catalysis: Fe 3d Electron Delocalization Matters
Author(s) -
Li Zilan,
Zhuang Zechao,
Lv Fan,
Zhu Han,
Zhou Liang,
Luo Mingchuan,
Zhu Jiexin,
Lang Zhiquan,
Feng Shihao,
Chen Wei,
Mai Liqiang,
Guo Shaojun
Publication year - 2018
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201803220
Subject(s) - moiety , catalysis , electron transfer , delocalized electron , materials science , oxygen , adsorption , oxidation state , spin states , carbon fibers , rational design , inorganic chemistry , photochemistry , chemistry , nanotechnology , stereochemistry , organic chemistry , composite number , composite material
Iron–nitrogen–carbon (Fe–N–C) is hitherto considered as one of the most satisfactory alternatives to platinum for the oxygen reduction reaction (ORR). Major efforts currently are devoted to the identification and maximization of carbon‐enclosed FeN 4 moieties, which act as catalytically active centers. However, fine‐tuning of their intrinsic ORR activity remains a huge challenge. Herein, a twofold activity improvement of pristine Fe–N–C through introducing Ti 3 C 2 T x MXene as a support is realized. A series of spectroscopy and magnetic measurements reveal that the marriage of FeN 4 moiety and MXene can induce remarkable Fe 3d electron delocalization and spin‐state transition of Fe(II) ions. The lower local electron density and higher spin state of the Fe(II) centers greatly favor the Fed z 2electron transfer, and lead to an easier oxygen adsorption and reduction on active FeN 4 sites, and thus an enhanced ORR activity. The optimized catalyst shows a two‐ and fivefold higher specific ORR activity than those of pristine catalyst and Pt/C, respectively, even exceeding most Fe–N–C catalysts ever reported. This work opens up a new pathway in the rational design of Fe–N–C catalysts, and reflects the critical influence of Fe 3d electron states in FeN 4 moiety supported on MXene in ORR catalysis.