The electrochemical hydrogen evolution reaction (HER) has become one of effective ways to produce hydrogen. MoS is a promising electrocatalyst for the HER, and loading noble metal atoms on MoS support can further enhance its HER activity. In present work, the CO was employed as a structure-directing agent to in situ synthesize MoS-n (n = 0, 0.5, 1.0, 1.4 and 2.0 MPa, representing the CO pressure). Among them, the MoS-1.4 with highest amounts of sulfur vacancies and superior alkaline HER performance was selected as the support for Ru loadings. Sulfur vacancies can stabilize Ru nanoparticles, prevent nanoparticles from aggregating, and facilitate the formation of small-sized nanoparticles. By optimizing the loading amounts of Ru, the 5Ru@MoS-1.4 with the Ru loading of 5 wt.% and nanoparticle size of 2 nm exhibits the best alkaline HER activity by displaying a low overpotential of 55 mV and Tafel slope of 68.6 mV dec at a current density of 10 mA cm in 1.0 M KOH medium. This can be majorly related to the synergistic effect of MoS-1.4 support and small-sized Ru nanoparticles, wherein the CO plays a significant role in regulating the structure of MoS-1.4 support that favors dispersion of Ru nanoparticles. Generally, present work provides a strategy to enhance the HER catalytic performance of MoS, which is favorable for other highly-efficient catalyst design.

中文翻译：

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MoS2负载的钌纳米粒子具有丰富的硫空位，显着改善析氢反应

电化学析氢反应（HER）已成为制氢的有效方法之一。 MoS2是一种很有前景的HER电催化剂，在MoS2载体上负载贵金属原子可以进一步增强其HER活性。在目前的工作中，CO被用作结构导向剂来原位合成MoS-n（n = 0、0.5、1.0、1.4和2.0 MPa，代表CO压力）。其中，选择具有最高硫空位量和优异的碱性HER性能的MoS-1.4作为Ru负载的载体。硫空位可以稳定Ru纳米粒子，防止纳米粒子聚集，并促进小尺寸纳米粒子的形成。通过优化 Ru 的负载量，Ru 负载量为 5 wt.%、纳米颗粒尺寸为 2 nm 的 5Ru@MoS-1.4 通过表现出 55 mV 的低过电势和 68.6 mV dec 的塔菲尔斜率，表现出最佳的碱性 HER 活性。在 1.0 M KOH 介质中，电流密度为 10 mA cm。这主要与MoS-1.4载体和小尺寸Ru纳米颗粒的协同效应有关，其中CO在调节MoS-1.4载体的结构方面发挥着重要作用，有利于Ru纳米颗粒的分散。总的来说，目前的工作提供了一种增强MoS2的HER催化性能的策略，这有利于其他高效催化剂的设计。