Rational design of efficient catalysts for ammonia (NH₃) synthesis at mild conditions is of paramount importance for the development of electrolysis driven Haber-Bosch (eHB) process. Ammonia synthesis is a structure sensitive reaction, and any small change of electronic structure could result in dramatic change of catalytic activity, especially for the Ru-based NH₃ synthesis catalysts. Electronic structure modulation of the Ru-based catalysts could provide desirable catalytic activity. Herein, we explore a class of Ru-Co single-atom alloy catalysts (marked as Ru_xCo₁ SAA, x stands for Ru/Co molar ratio), in which Co single atoms are located on Ru nanoclusters to form Co-Ru coordination, and then electronic structure of Ru_xCo₁ SAA could be effectively tuned by regulating the Ru/Co molar ratio. Our studies show that a moderate ratio of Ru/Co (1.7:1) favors superior NH₃ synthesis rate and low activation energy. Using a suite of elaborate characterizations, we have observed that the outstanding performance over Ru_1.7Co₁ SAA can be attributed to the electron redistribution between Ru and Co atom, resulting in an upshift of d band center and lowering of work function. However, there is decrease of NH₃ synthesis rate when Ru/Co molar ratio is 2, due to the partial detachment of Ru entities from SAA structure, and the formed individual Ru nanoparticles (NPs) overlay the surface of catalyst. In such a case, N₂ activation behavior over Ru₂Co₁ is alike that of Ru NPs catalysts. The present study demonstrates that the Ru/Co ratio in SAA structure can effectively regulate the electronic structure of catalyst for NH₃ synthesis rate enhancement.

_{在温和条件下合理设计用于氨 (NH 3} ) 合成的高效催化剂对于开发电解驱动的 Haber-Bosch ( e HB) 工艺至关重要。氨合成是一种结构敏感的反应，电子结构的任何微小变化都会导致催化活性的剧烈变化，尤其是对于Ru基NH ₃合成催化剂。Ru基催化剂的电子结构调节可以提供理想的催化活性。在此，我们探索了一类Ru-Co单原子合金催化剂（标记为Ru _x Co ₁SAA，x代表Ru/Co摩尔比），其中Co单原子位于Ru纳米团簇上形成Co-Ru配位，然后通过调节Ru/Co摩尔比可以有效调节Ru _x Co ₁ SAA的电子结构比率。我们的研究表明，适度的 Ru/Co 比 (1.7:1) 有利于出色的 NH ₃合成速率和低活化能。通过一系列详尽的表征，我们观察到 Ru _1.7 Co ₁ SAA 的出色性能可归因于 Ru 和 Co 原子之间的电子重新分布，导致d带中心上移和功函数降低。然而，NH _3减少当Ru/Co摩尔比为2时，由于Ru实体部分从SAA结构中脱离，形成的单个Ru纳米颗粒（NPs）覆盖在催化剂表面，从而提高了合成速率。在这种情况下， Ru ₂ Co _{1上的 N 2}活化行为与 Ru NPs 催化剂相似。本研究表明，SAA结构中的Ru/Co比可以有效调节催化剂的电子结构，从而提高NH ₃合成速率。