Electrochemical nitrogen reduction reaction (NRR) is one of the most promising alternatives to the traditional Haber-Bosch process. Designing efficient electrocatalysts is still challenging. Inspired by the recent experimental and theoretical advances on single-cluster catalysts (SCCs), we systematically investigated the catalytic performance of various triple-transition-metal-atom clusters anchored on nitrogen-doped graphene for NRR through density functional theory (DFT) calculation. Among them, Mn₃-N4, Fe₃-N4, Co₃-N4, and Mo₃-N4 were screened out as electrocatalysis systems composed of non-noble metal with high activity, selectivity, stability, and feasibility. Particularly, the Co₃-N4 possesses the highest activity with a limiting potential of −0.41 V through the enzymatic mechanism. The outstanding performance of Co₃-N4 can be attributed to the unique electronic structure leading to strong π backdonation, which is crucial in effective N₂ activation. This work not only predicts four efficient non-noble metal electrocatalysts for NRR, but also suggest the SCCs can serve as potential candidates for other important electrochemical reactions.

电化学氮还原反应（NRR）是传统Haber-Bosch工艺最有希望的替代方法之一。设计有效的电催化剂仍然具有挑战性。受单簇催化剂（SCC）的最新实验和理论进展的启发，我们通过密度泛函理论（DFT）计算，系统地研究了锚固在氮掺杂石墨烯上的各种三重过渡金属原子簇对NRR的催化性能。其中，Mn ₃ -N4，Fe ₃ -N4，Co ₃ -N4和Mo ₃ -N4被筛选为具有高活性，选择性，稳定性和可行性的非贵金属组成的电催化体系。特别是Co ₃-N4具有最高的活性，通过酶促机制的极限电位为-0.41V。Co ₃ -N4的出色性能可归因于独特的电子结构，该结构可导致强烈的π返配，这对于有效的N ₂活化至关重要。这项工作不仅预测了NRR的四种有效的非贵金属电催化剂，而且表明SCC可以作为其他重要电化学反应的潜在候选者。