Chinese Journal of Catalysis ›› 2025, Vol. 75: 73-83.DOI: 10.1016/S1872-2067(25)64715-2

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Se-doping strategy regulating mass transfer and electronic structure of Fe-N-C electrocatalysts for proton exchange membrane fuel cells

Lin Xua,1, Li Danyanga,1, Huang Shiqinga,1, Sun Panpana, Huang Yana, Wang Shitaoa, Zheng Lirongb,*(), Cao Dapenga,*()   

  1. aState Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China
    bBeijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
  • Received:2025-02-05 Accepted:2025-03-24 Online:2025-08-18 Published:2025-07-22
  • Contact: *E-mail: zhenglr@ihep.ac.cn (L. Zheng), caodp@buct.edu.cn (D. Cao).
  • About author:1Contributed equally to this work.
  • Supported by:
    National Key Research and Development Project from MOST(2019YFA0210300);National Natural Science Foundation of China(22372006)

Abstract:

The limited activity of atomically-dispersed M-N-C electrocatalysts severely restricts their applicability in the oxygen reduction reaction (ORR) for proton exchange membrane fuel cells (PEMFC). Herein, we design and synthesize Se-doped Fe-N-C hierarchical porous electrocatalyst (FeN4/SeC2) by optimizing carbon structure and FeN4 coordination environment. The FeN4/SeC2 electrocatalyst exhibits outstanding ORR activity in 0.1 mol L-1 HClO4, and the resulting PEMFC presents a peak power density of 1.20 W cm-2 in H2-O2 condition at a back pressure of 200 kPa, ranking in the top levels among most reported non-precious metal catalyst-based fuel cells. The lower O2 transfer resistance of FeN4/SeC2-based membrane electrode assembly than FeN4-based one means faster O2 transport in triple-phase boundary (TPB), and Density functional theory calculation further reveals that the synergistic catalysis between porous SeC2 and FeN4-OH species can efficiently lower the energy barriers for the rate-determining step of the ORR. In short, the outstanding performance of FeN4/SeC2 in PEMFC is ascribed to the Se-doping, which introduces more defects and larger mesoporosity and therefore facilitates ionomer infiltration and O2 transfer and charge transfer in TPB. The effective strategy of enhancing mass and charge transfers in TPB is anticipated to be applicable in the construction of highly efficient ORR electrocatalysts.

Key words: Se-doping, Synergistic catalysis, Enhancing mass transfer, Oxygen reduction, Proton exchange membrane fuel cells