Fe-N-C electrocatalysts,comprising FeN4 single atom sites immobilized on N-doped carbon supports,offer excellent activity in the oxygen reduction reaction(ORR),especially in alkaline solution.Herein,we report a simple synthetic strategy for improving the accessibility of FeN4 sites during ORR and simul-taneously fine-tuning the microenvironment of FeN4 sites,thus enhancing the ORR activity.Our approach involved a simple one-step pyrolysis of a Fe-containing zeolitic imidazolate framework in the presence of NaCl,yielding a hierarchically porous Fe-N-C electrocatalyst containing tailored FeN4 sites with slightly elongated Fe-N bond distances and reduced Fe charge.The porous carbon structure improved mass transport during ORR,whilst the microenvironment optimized FeN4 sites benefittted the adsorption/des-orption of ORR intermediates.Accordingly,the developed electrocatalyst,possessing a high FeN4 site density(9.9×1019 sites g-1)and turnover frequency(2.26 s-1),delivered remarkable ORR performance with a low overpotential(a half-wave potential of 0.90 V vs.reversible hydrogen electrode)in 0.1 mol L-1 KOH.

Qing Wang;Ruihu Lu;Yuqi Yang;Xuanze Li;Guangbo Chen;Lu Shang;Lishan Peng;Dongxiao Sun-Waterhouse;Bruce C.C.Cowie;Xiangmin Meng;Yan Zhao;Tierui Zhang;Geoffrey I.N.Waterhouse

School of Chemical Sciences,The University of Auckland,Auckland 1142,New Zealand;State Key Laboratory of Silicate Materials for Architectures,International School of Materials Science and Engineering,Wuhan University of Technology,Wuhan 430070,China;iHuman Institute,ShanghaiTech University,Shanghai 201210,China;Key Laboratory of Photochemical Conversion and Optoelectronic Materials,Technical Institute of Physics and Chemistry,Chinese Academy of Sciences,Beijing 100190,China;Australian Synchrotron,800 Blackburn Rd.,Clayton,Victoria 3168,Australia

科学通报（英文版）

[1]Qing Wang;Ruihu Lu;Yuqi Yang;Xuanze Li;Guangbo Chen;Lu Shang;Lishan Peng;Dongxiao Sun-Waterhouse;Bruce C.C.Cowie;Xiangmin Meng;Yan Zhao;Tierui Zhang;Geoffrey I.N.Waterhouse-.Tailoring the microenvironment in Fe-N-C electrocatalysts for optimal oxygen reduction reaction performance)[J].科学通报（英文版）,2022(12):1264-1273

FeN4,benefittted

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