Fine tuning the work function difference (ΔΦ) between support and Ru which in turn affects the electron distribution of Ru is an effective method for the design of high-performance alkaline hydrogen evolution reaction (HER) catalysts. However, it remains a challenge to understand the intrinsic relationship between HER activity and ΔΦ at the atomic level. Herein, taking N doped graphene supported Ru nanoclusters (Ru/CN) as the theoretical model, we demonstrate that the HER activity can be correlated with the variation of ΔΦ. For Ru/C with smaller ΔΦ, we find that the Ru atoms located at the top layer of Ru nanoclusters (Ru-t) with lower coordination numbers are the main reaction sites. For Ru/CN with larger ΔΦ, the stronger charge redistributions of Ru is observed, and the electron-deficient Ru atoms closing to the interface (Ru-i) are the main reaction sites with significant improvement HER activity. Our findings demonstrate the role of ΔΦ on Ru/CN systems for the alkaline HER, which can provide valuable theoretical guidance for the design of high efficient HER catalysts.

中文翻译：

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揭示功函数差异对负载型 Ru 纳米团簇在碱性析氢反应中的作用

微调载体和Ru之间的功函数差（ΔΦ）进而影响Ru的电子分布是设计高性能碱性析氢反应（HER）催化剂的有效方法。然而，在原子水平上理解 HER 活性和 ΔΦ 之间的内在关系仍然是一个挑战。在此，以N掺杂石墨烯负载Ru纳米团簇（Ru/CN）为理论模型，我们证明HER活性可以与ΔΦ的变化相关。对于ΔΦ较小的Ru/C，我们发现位于配位数较低的Ru纳米团簇（Ru-t）顶层的Ru原子是主要反应位点。对于ΔΦ越大的Ru/CN，观察到Ru的电荷重新分布越强，并且靠近界面（Ru-i）的缺电子Ru原子是HER活性显着提高的主要反应位点。我们的研究结果证明了 ΔΦ 对 Ru/CN 体系中碱性 HER 的作用，这可以为高效 HER 催化剂的设计提供有价值的理论指导。