以ZIF-8为模板，通过表面包覆聚多巴胺、同时刻蚀ZIF-8中的Zn²⁺，形成空心球，在与三氯化铁络合后，经高温碳化和氨气热处理，得到了高比表面积的Fe-N共掺杂的碳纳米管串联的碳纳米空心球催化剂. 氨气不仅刻蚀碳基底提高比表面积，还可还原铁元素形成Fe₄N纳米粒子，提升了催化剂对氧还原反应的电催化活性，其氧还原半波电位达0.79 V，仅比商业Pt/C低60 mV，而且其稳定性和耐甲醇性更优于商业Pt/C，展示出良好的燃料电池应用潜力.

The development of non-precious metal catalysts for oxygen reduction reaction (ORR) is essential for large-scale application of proton exchange membrane fuel cells. Herein, we present the in situ formed Fe-N doped hollow carbon nanospheres linked by carbon nanotubes composite, synthesized by using ZIF-8 as sacrificed template to form polydopamine (PDA) hollow nanospheres, followed by complexing with FeCl₃, high temperature heat-treatment and NH₃-etching. ZIF-8 was gradually decomposed simultaneously with PDA coating due to the loss of Zn²⁺ grabbed by PDA. NH3 etching resulted in the improved surface area, while the reducibility of NH₃ resulted in the formation of Fe₄N nanoparticles, which benefits the ORR activity of the catalyst. The half-wave potential of the as-prepared of PDA-Fe/N/C-NH₃ was 0.79 V, only 60 mV lower than that of commercial Pt/C. The stability and methanol tolerance of PDA-Fe/N/C-NH₃ were even superior to that of commercial Pt/C, indicating the good potential of PDA-Fe/N/C-NH₃ for the application of fuel cells.