Molybdenum sulfide is an intensely attractive noble-metal-free electrocatalyst for the hydrogen evolution reaction (HER). How to enhance electrical conductivity and maintain high intrinsic activity and active site density remains a challenge. Herein, we design a novel composite catalyst, which is composed of molybdenum sulfide clusters and defective graphene, holding excellent intrinsic activity, high-density active sites and high conductivity simultaneously. The strong S–C covalent bonds between clusters and graphene ensure the structural stability of the composite, avoiding the long-standing deactivation problem caused by cluster desorption. The clusters possess high-density active sites and the graphene acts as the conducting path to transport electrons from the electrode to active sites efficiently. Moreover, the simulations of diffusion of clusters on defective graphene demonstrate that the composite catalyst is easy to synthesize by a simple drop-casting procedure.

中文翻译：

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固定在有缺陷的石墨烯上的硫化钼簇：是析氢反应的稳定催化剂†

硫化钼是一种极具吸引力的氢气释放反应（HER）的无贵金属电催化剂。如何提高电导率并保持高固有活性和活性位点密度仍然是一个挑战。本文中，我们设计了一种新型的复合催化剂，该催化剂由硫化钼簇和有缺陷的石墨烯组成，同时具有优异的固有活性，高密度活性位点和高电导率。团簇和石墨烯之间的强S-C共价键确保了复合材料的结构稳定性，避免了由团簇解吸引起的长期失活问题。团簇具有高密度的活性位点，石墨烯充当了将电子从电极有效地传输到活性位点的传导路径。而且，