Electrocatalytic nitrogen fixation is crucial for sustainable NH₃ production, however it still suffers from sluggish kinetics. Here, we report that single-layer MoS₂ with adjacent Mo sites (A-Mo-MoS₂) prepared by preciously controlling the oriented topological conversion could exhibit an exceptional NH₃ yield rate of 48.8 µg h^–1 mg^–1 and Faradic efficiency (FE) of 27.3 % at −0.20 V vs. RHE, far beyond MoS₂ with isolated sulfur vacancies (I-SV-MoS₂) with a 18.8 µg h^–1 mg^–1 rate and 8.4 % FE. Theoretical analysis reveal that A-Mo-MoS₂ could induce their unpaired spin-polarized electrons to share along the outermost Mo edge, thereby forming a grand spin-delocalized electrons reservoir. Compared to limited spin-localized electrons on I-SV-MoS₂, these spin-delocalized electrons could significantly facilitate nitrogen activation and switched the rate-determining step from energy-demanding *N₂ hydrogenation to surmountable *HNNH hydrogenation. Our work offers a new strategy to promote nitrogen fixation by spin-delocalized electrons effect.

电催化固氮对于可持续的 NH ₃生产至关重要，但它仍然存在动力学缓慢的问题。在这里，我们报告了通过精确控制定向拓扑转换制备的具有相邻 Mo 位点的单层 MoS ₂ (A-Mo-MoS _{2 ) 可以表现出 48.8 µg h} ^–1 mg ^–1的异常 NH ₃产率和法拉第效率(FE) 在 −0.20 V 相对于 RHE 时为 27.3%，远远超过具有孤立硫空位的 MoS 2 (I-SV-MoS _{2 )}，速率为 18.8 µg h ^–1 mg ^–1和 8.4 % FE。理论分析表明A-Mo-MoS ₂可以诱导它们未成对的自旋极化电子沿着最外层的 Mo 边缘共享，从而形成一个大的自旋离域电子库。与 I-SV-MoS ₂上有限的自旋定域电子相比，这些自旋离域电子可以显着促进氮活化，并将决速步骤从需要能量的 *N ₂氢化转变为可克服的 *HNNH 氢化。我们的工作提供了一种通过自旋离域电子效应促进固氮的新策略。