The central theme in single-atom catalysis is to build strong interactions between the single atoms and the support for stabilization in electrocatalytic nitrogen reduction reaction (eNRR). Herein, we utilize the well-defined ab initio computations to build up the strong coupling systems between single atoms and transition metal borides (MBene) as the superior electrocatalysts for eNRR. This work addresses a series of transition metal atoms ranging from IVB to VIII subgroups in Mo vacancies of the MBene nanosheet (Mo₂B₂O₂) and carries out a systematic screening of activities and selectivity on the eNRR process. The computational results indicate that Re and Os supported on the defective Mo₂B₂O₂ layer possess a remarkable catalytic activity with relatively low barrier of the potential-determining step (PDS) of 0.29 and 0.32 eV, which are lower than that of the single Ru atom decorated on Mo₂CO₂ (0.46 eV). The implanted Re and Os atoms selectively promote the eNRR process and suppress the hydrogen evolution reaction (HER) process in the presence of oxygen vacancies. Moreover, the number of d electrons and the horizontal periods in periodic table of the elements of single atoms are proved to be related to the first protonation step of eNRR and the crucial adsorbed species *NNH. Accordingly, the binary descriptor with respect to the number of d electrons and the period is proposed to establish the relationship between the intrinsic atomic properties and catalytic capacity. This work paves the way to the electrocatalytic atomic-level mechanism of novel MBene for the reduction of N₂ to NH₃ at ambient conditions.

中文翻译：

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嵌入MBene的单金属原子电催化转化N ₂到NH _3的密度泛函理论研究

单原子催化的中心主题是在单原子与电催化氮还原反应（eNRR）稳定化载体之间建立强相互作用。在这里，我们利用定义明确的从头算来建立单原子与过渡金属硼化物（MBene）之间的强耦合系统，作为eNRR的优良电催化剂。这项工作解决了在MBene纳米片的Mo空位（Mo ₂ B ₂ O ₂）中从IVB到VIII子族的一系列过渡金属原子，并对eNRR过程的活性和选择性进行了系统的筛选。计算结果表明，Re和Os负载在有缺陷的Mo ₂ B _2上。O ₂层具有显着的催化活性，势能确定步骤（PDS）的势垒相对较低，为0.29和0.32 eV，低于在Mo ₂ CO ₂上修饰的单个Ru原子的势垒（0.46 eV）。注入的Re和Os原子在存在氧空位的情况下选择性地促进eNRR过程并抑制氢释放反应（HER）过程。此外，单原子元素周期表中的d电子数量和水平周期被证明与eNRR的质子化第一步以及关键的吸附物质* NNH有关。因此，提出了关于d电子数和周期的二元描述符，以建立固有原子性质与催化能力之间的关系。这项工作为新型MBene在环境条件下将N ₂还原为NH ₃铺平了道路。