NH₃ synthesis on Ru, Os, and Rh nanoparticle catalysts was investigated using density functional theory calculations. The Ru and Os nanoparticles exhibited similar shapes, while that of Rh differed significantly. For all metal species, step sites appeared at nanoparticle diameters (d) >2–4 nm. The calculated activation barriers (E_a) were small at step sites, and Ru and Os step sites exhibited similar E_a values despite the former having a higher turnover frequency. This is likely due to the surface coverage of vacant sites being higher on Ru. Although the increase in NH₃ synthesis rate at d = 2–4 nm was common to Ru, Os, and Rh, the reaction rates decreased in the order: Ru > Os > Rh. Our results show that E_a values, surface vacant sites, and the number of step sites are important factors for NH₃ synthesis. The Ru nanoparticles exhibited high activity due to satisfying all three factors.

使用密度泛函理论计算研究了Ru，Os和Rh纳米颗粒催化剂上的NH ₃合成。Ru和Os纳米粒子表现出相似的形状，而Rh则明显不同。对于所有金属种类，阶跃点出现在纳米粒子直径（d）> 2-4 nm处。计算出的活化势垒（E _a）在台阶部位很小，Ru和Os台阶部位显示相似的E _a值，尽管前者的翻转频率较高。这可能是由于Ru上空位的表面覆盖率较高。尽管在d时NH _3的合成速率增加 = 2–4 nm是Ru，Os和Rh共有的，反应速率按以下顺序降低：Ru> Os> Rh。我们的结果表明，E _a值，表面空位和步阶数量是NH ₃合成的重要因素。由于满足所有三个因素，Ru纳米颗粒表现出高活性。