As the continuous development of electrocatalytic technique, the degradation of toxic nitrate wastewater into green fuel ammonia has become the goal of researcher’s unremitting efforts by electrochemical method. Particularly, a high performance catalyst for electrochemical process is regarded as an indispensable tool for sustainable cycle. Although existing designed electrodes may effectively advance nitrate reduction reaction, they remain unsatisfactory due to elusive reaction processes. Here, a brand-new reaction mechanism has been proposed via density functional theory (DFT) and ab initio molecule dynamic (AIMD) methods, which breaks the bottleneck of linear scaling in atomic scale catalyst design. It is found that triple Mn atoms anchored on graphdiyne (Mn₃-GDY) can drive nitrate adsorption and ammonia desorption on its surface with weak binding strength and strong activation by the spin polarization of active site. In addition, the powerful adsorption capacity of triatomic active site prevents the thermodynamic barrier from rising due to the transformation of the intermediates *NO₃H and *NO₂H into *NO₂*OH and *NO*OH, respectively. More importantly, in accordance with the “weak-strong-weak” principle, Mn₃-GDY has rapid response to ammonia desorption that is conducive to boost the turnover frequency. Anyway, this work may provide a new insight into atomic catalysts for improving reaction mechanisms.

随着电催化技术的不断发展，利用电化学方法将有毒的硝酸盐废水降解为绿色燃料氨已成为研究人员不懈努力的目标。特别是，用于电化学过程的高性能催化剂被认为是可持续循环不可或缺的工具。尽管现有设计的电极可以有效地促进硝酸盐还原反应，但由于难以捉摸的反应过程，它们仍然不能令人满意。在这里，通过密度泛函理论（DFT）和从头算分子动力学（AIMD）方法提出了一种全新的反应机制，打破了原子尺度催化剂设计中线性缩放的瓶颈。发现锚定在石墨二炔（Mn ₃-GDY) 可以通过活性位点的自旋极化驱动其表面的硝酸盐吸附和氨解吸，结合强度弱，活化强。此外，由于中间体*NO ₃ H 和*NO ₂ H 分别转化为*NO ₂ *OH 和*NO*OH，三原子活性位点的强大吸附能力可防止热力学势垒上升。更重要的是，按照“弱-强-弱”的原则，Mn ₃ -GDY对氨解吸反应迅速，有利于提高周转频率。无论如何，这项工作可能会为改进反应机制的原子催化剂提供新的见解。