Tailoring the local environment and electronic structure of the active center of M-N-C catalysts is a promising route to improve the performance of catalysts. Herein, we design and controllably synthesize an O-doped O-FeN₄C-O catalyst and identify its local structure, which contains two kinds of oxygen doping, i.e., axial-oxygen doping and second-coordination-shell oxygen doping of FeN₄ species. Density functional theory calculations reveal that the synergy of the two kinds of oxygen doping optimizes electronic structure and therefore boosts oxygen reaction reduction (ORR) performance. Consequently, the O-FeN₄C-O exhibits excellent ORR activities in both acidic and alkaline conditions. Importantly, the O-FeN₄C-O-based proton- and anion-exchange membrane fuel cells deliver ultra-high peak power densities of 0.88 and 1.24 W cm⁻², which ranked among the top performers of non-precious-metal ORR catalysts-based fuel cells. This work paves a new avenue for designing M-N₄-X (X = P, S, etc.) catalysts with tunable electronic structures for different electrocatalysis, including carbon dioxide and nitrogen reduction and oxygen and hydrogen evolution.

调整MNC催化剂活性中心的局部环境和电子结构是提高催化剂性能的一条有希望的途径。在此，我们设计并可控合成了一种O掺杂的O-FeN ₄ CO催化剂并鉴定了其局部结构，该催化剂包含两种氧掺杂，即FeN ₄的轴向氧掺杂和第二配位壳氧掺杂。密度泛函理论计算表明，两种氧掺杂的协同作用优化了电子结构，从而提高了氧反应还原 (ORR) 性能。因此，O-FeN ₄ CO -O 在酸性和碱性条件下均表现出优异的 ORR 活性。重要的是，O-FeN ₄^{基于CO的质子和阴离子交换膜燃料电池提供0.88和1.24 W cm -2}的超高峰值功率密度，在基于非贵金属ORR催化剂的燃料电池中名列前茅。这项工作为设计具有可调电子结构的 MN ₄ -X（X = P、S 等）催化剂开辟了一条新途径，用于不同的电催化，包括二氧化碳和氮的还原以及氧气和氢气的析出。