Journal of Energy Chemistry ›› 2023, Vol. 85 ›› Issue (10): 154-163.DOI: 10.1016/j.jechem.2023.06.007

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Tuning the charge distribution and crystal field of iron single atoms via iron oxide integration for enhanced oxygen reduction reaction in zinc-air batteries

Feifei Zhanga, Yinlong Zhub,*, Yijun Zhongc, Jing Zoud, Yu Chene, Lianhai Zuf, Zhouyou Wanga, Jack Jon Hinschg, Yun Wangg,*, Lian Zhanga, Zongping Shaoc, Huanting Wanga,*   

  1. aDepartment of Chemical and Biological Engineering, Monash University, Clayton, VIC 3800, Australia;
    bInstitute for Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, Jiangsu, China;
    cWA School of Mines: Minerals, Energy and Chemical Engineering (WASM-MECE), Curtin University, Perth, WA 6102, Australia;
    dKey Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China;
    eMonash Centre for Electron Microscopy, Monash University, Clayton, VIC 3800, Australia;
    fDepartment of Chemical Engineering, The University of Melbourne, Parkville, VIC 3010, Australia;
    gCentre for Catalysis and Clean Energy, School of Environment and Science, Griffith University, Gold Coast Campus, Southport, QLD 4222, Australia
  • Received:2023-05-04 Revised:2023-06-09 Accepted:2023-06-12 Online:2023-10-15 Published:2023-11-06
  • Contact: *E-mail addresses: zhuyl1989@nuaa.edu.cn (Y. Zhu), yun.wang@griffith.edu.au (Y. Wang), huanting.wang@monash.edu (H. Wang).

Abstract: Metal-air batteries face a great challenge in developing efficient and durable low-cost oxygen reduction reaction (ORR) electrocatalysts. Single-atom iron catalysts embedded into nitrogen doped carbon (Fe-N-C) have emerged as attractive materials for potential replacement of Pt in ORR, but their catalytic performance was limited by the symmetrical electronic structure distribution around the single-atom Fe site. Here, we report our findings in significantly enhancing the ORR performance of Fe-N-C by moderate Fe2O3integration via the strong electronic interaction. Remarkably, the optimized catalyst (M-Fe2O3/FeSA@NC) exhibits excellent activity, durability and good tolerance to methanol, outperforming the benchmark Pt/C catalyst. When M-Fe2O3/FeSA@NC catalyst was used in a practical zinc-air battery assembly, peak power density of 155 mW cm-2and specific capacity of 762 mA h gZn-1 were achieved and the battery assembly has shown superior cycling stability over a period of 200 h. More importantly, theoretical studies suggest that the introduction of Fe2O3 can evoke the crystal field alteration and electron redistribution on single Fe atoms, which can break the symmetric charge distribution of Fe-N4 and thereby optimize the corresponding adsorption energy of intermediates to promote the O2 reduction. This study provides a new pathway to promote the catalytic performance of single-atom catalysts.

Key words: Single-atom catalysts, Oxide nanoclusters, Electronic interactions, Oxygen reduction reaction, Zn-air battery