Developing single-atomic site (SAS) catalysts for oxygen reduction reaction (ORR) with superior activities in the renewable-energy initiatives is critical but remains challenging. Herein, exceptional SAS Fe boosted by adjacent graphene-encapsulated Fe₃C nanocrystals (Fe₃C@C-Fe SAS) is constructed for ORR. Because of the strong synergistic effects between SAS Fe and Fe₃C@C nanocrystals, Fe₃C@C-Fe SAS shows robust ORR performance in the neutral electrolyte with the onset potential of 0.99 V and negligible activity loss after 30 k cycles of an accelerated durability test, much better than that of Pt/C catalyst. Notably, the integrated zinc-air battery in the neutral system exhibits an outstanding peak power density of 74.8 mW/cm² and durability over 100 h, representing a state-of-the-art PGM-free ORR catalyst. More importantly, the density functional theory (DFT) calculations shed light on that the introduction of Fe₃C@C nanocrystals is favorable for the activation of O₂ molecules and desorption of OH* on the Fe SAS, resulting in accelerated reaction kinetics and promising ORR activity. Given the explicit structure-performance relationships for Fe₃C@C-Fe SAS, this work provides a new strategy for the design of more advanced energy-based electrocatalysts.

开发可再生能源计划中具有卓越活性的氧还原反应（ORR）的单原子位（SAS）催化剂至关重要，但仍具有挑战性。在此，为ORR构建了由相邻的石墨烯包裹的Fe ₃ C纳米晶体（Fe ₃ C @ C-Fe SAS）增强的特殊SAS Fe 。由于SAS Fe和Fe ₃ C @ C纳米晶体之间有很强的协同作用，Fe ₃ C @ C-Fe SAS在中性电解质中显示出强大的ORR性能，起始电势为0.99 V，经过30 k次循环后的活性损失可忽略加速耐久性测试，远优于Pt / C催化剂。值得注意的是，中性系统中集成的锌-空气电池具有出色的峰值功率密度，为74.8 mW / cm²和100小时以上的耐久性，代表了最先进的无PGM的ORR催化剂。更重要的是，密度泛函理论（DFT）的计算表明，引入Fe ₃ C @ C纳米晶体有利于O ₂分子的活化和OH *在Fe SAS上的解吸，从而加快了反应动力学，并具有广阔的前景ORR活动。鉴于Fe ₃ C @ C-Fe SAS具有明确的结构-性能关系，这项工作为设计更高级的基于能量的电催化剂提供了新的策略。