Metal-nitrogen-carbon materials have been demonstrated as the most promising non-noble metal catalyst for proton-exchange membrane fuel cells (PEMFCs) but are still limited by the sluggish kinetics and durability of metal-nitrogen active sites. Here, we unravel a planar-like Fe₂N₆ active site as a highly efficient oxygen reduction catalyst for PEMFCs. Our developed planar-like Fe₂N₆ structure behaves as a distinguished catalytic mechanism for oxygen reduction, which brings synergic advantages of accelerated catalytic kinetics and highly suppressed side reaction, successfully promoting its catalytic activity and stability. As expected, the planar-like Fe₂N₆ structure with high density exhibits over 700% increase in mass activity than traditional isolated iron-nitrogen sites. Moreover, a PEMFC built with this catalyst also achieves a large peak power density of 845 mW cm⁻², representing a critical breakthrough for practical application of metal-nitrogen-carbon materials in PEMFC systems. Our findings will provide a new avenue toward designing highly active metal-nitrogen sites for heterogeneous catalysis.

金属氮碳材料已被证明是质子交换膜燃料电池（PEMFC）最有前途的非贵金属催化剂，但仍然受到金属氮活性位的反应迟钝的动力学和耐久性的限制。在这里，我们将平面状的Fe ₂ N ₆活性位点解开，作为PEMFC的高效氧还原催化剂。我们开发的平面状Fe ₂ N ₆结构可作为一种独特的氧还原催化机理，它具有加速催化动力学和高度抑制副反应的协同优势，成功地提高了其催化活性和稳定性。不出所料，平面状的Fe ₂ N ₆与传统的分离的铁-氮位点相比，高密度的结构显示出超过700％的质量活性增加。此外，用该催化剂构建的PEMFC还实现了845 mW cm ^-2的大峰值功率密度，这代表了金属氮碳材料在PEMFC系统中的实际应用的关键突破。我们的发现将为设计用于多相催化的高活性金属氮位点提供一条新途径。