Although nonprecious metal catalysts based on earth-abundant 3d transition metals (TMs) are regarded as promising substitutes for a noble metal electrocatalytic hydrogen evolution reaction (HER), their large-scale application is still inhibited by their inadequate activity and durability. Here, a facile method for nonprecious metal catalysts has been developed to prepare molybdenum carbide on nitrogen-doped carbon. By optimizing the Ni doping ratio, the Ni_0.5@MoC_x/NC exhibits the lowest overpotential for 10 mA cm^–2 and superior stability in both acidic and alkaline media for HER application, outperforming most of the reported HER electrocatalysts. In addition, a theoretical simulation has also confirmed the possible mechanism for the synergistic effect with the regulative adsorption energy of hydrogen species with Ni doping and formation of a Mo₂C/MoC heterojunction in the Ni_0.5@MoC_x/NC electrocatalyst. Therefore, this work provides a new avenue for designing two-dimensional nanostructures with an optimized electronic structure for promising TM HER electrocatalysts in a wide pH range.

中文翻译：

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Ni掺杂和Mo ₂ C / MoC异质结的集成，用于在酸性和碱性条件下释放氢

尽管基于地球上丰富的3d过渡金属（TMs）的非贵金属催化剂被认为是贵金属电催化氢析出反应（HER）的有前途的替代品，但它们的大规模应用仍然受到活性和耐久性不足的限制。在此，已经开发了一种用于非贵金属催化剂的简便方法，以在掺氮碳上制备碳化钼。通过优化Ni掺杂比，Ni _0.5 @MoC _x / NC在10 mA cm ^–2时表现出最低的过电势在用于HER的酸性和碱性介质中均具有出色的稳定性，胜过大多数已报道的HER电催化剂。另外，理论模拟也证实了可能的机制，其与Ni掺杂的氢物种的调节吸附能的协同作用以及在Ni _0.5 @MoC _x / NC电催化剂中形成Mo ₂ C / MoC异质结。因此，这项工作为设计具有最佳电子结构的二维纳米结构提供了新的途径，从而有望在宽pH范围内实现TM HER电催化剂。