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Highly active sites of low spin FeIIN4 species: The identification and the ORR performance

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Abstract

Over recent years, catalytic materials of Fe-N-C species have been recognized being active for oxygen reduction reaction (ORR). However, the identification of active site remains challenging as it generally involves a pyrolysis process and mixed components being obtained. Herein Fe3C/C and Fe2N/C samples were synthesized by temperature programmed reduction of Fe precursors in 15% CH4/H2 and pure NH3, respectively. By acid leaching of Fe2N/C sample, only single sites of FeN4 species were presented, providing an ideal model for identification of catalytic functions of the single sites of FeN4 in ORR. A correlation was conducted between the concentration of FeIIN4 in low spin state by Mössbauer spectra and the kinetic current density at 0.8 V in alkaline media, and such a structure-performance correlation assures the catalytic roles of low spin FeIIN4 species as highly active sites for the ORR.

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Acknowledgements

The work was supported by the National Key R&D Program of China (No. 2017YFA0700103), the National Natural Science Foundation of China (Nos. 21932002, 21872014, 21707015, 21902018, and 21577013), the Postdoctoral Science Foundation of China (Nos. 2019T120210, 2018M641687) and the Natural Science Foundation of Liaoning Province (No. 2019-MS-053).

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  1. State Key Laboratory of Fine Chemicals, College of Chemical Engineering, Dalian University of Technology, Dalian, 116024, China

    Huizhu Cai, Bingbing Chen, Xiao Zhang & Chuan Shi

  2. College of Chemistry and Molecular Engineering and College of Engineering, Peking University, Beijing, 100871, China

    Yuchen Deng & Ding Ma

  3. Center for Integrative Materials Discovery, Department of Chemistry and Chemical Engineering, University of New Haven, New Haven, CT, 06516, USA

    Dequan Xiao

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  1. Huizhu Cai
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Cai, H., Chen, B., Zhang, X. et al. Highly active sites of low spin FeIIN4 species: The identification and the ORR performance. Nano Res. 14, 122–130 (2021). https://doi.org/10.1007/s12274-020-3054-8

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