Developing highly efficient and stable non-precious metal catalysts for water splitting is urgently required. In this work, we report a facile one-step molten salt method for the preparation of self-supporting Ni-doped Mo₂C on carbon fiber paper (Ni-Mo₂C_CB/CFP) for hydrogen evolution reaction (HER). The effects of nickel nitrate concentration on the phase composition, morphology, and electrocatalytic HER performance of Ni-doped Mo₂C@CFP electrocatalysts was investigated. With the continuous increase of Ni(NO₃)₂ concentration, the morphology of Mo₂C gradually changes from granular to flower-like, providing larger specific surface area and more active sites. Doping nickel (Ni) into the crystal lattice of Mo₂C largely reduces the impedance of the electrocatalysts and enhances their electrocatalytic activity. The as-developed Mo₂C-3 M Ni(NO₃)₂/CFP electrocatalyst exhibits high catalytic activity with a small overpotential of 56 mV at a current density of 10 mA·cm⁻². This catalyst has a fast HER kinetics, as demonstrated by a very small Tafel slope of 27.4 mV·dec⁻¹, and persistent long-term stability. A further higher Ni concentration had an adverse effect on the electrocatalytic performance. Density functional theory (DFT) calculations further verified the experimental results. Ni doping could reduce the binding energy of Mo-H, facilitating the desorption of the adsorbed hydrogen (H_ads) on the surface, thereby improving the intrinsic catalytic activity of Ni-doped Mo₂C-based catalysts. Nevertheless, excessive Ni doping would inhibit the catalytic activity of the electrocatalysts. This work not only provides a simple strategy for the facile preparation of non-precious metal electrocatalysts with high catalytic activity, but also unveils the influence mechanism of the Ni doping concentration on the HER performance of the electrocatalysts from the theoretical perspective.

迫切需要开发高效稳定的非贵金属水分解催化剂。在这项工作中，我们报告了一种简便的一步熔盐法，用于在碳纤维纸 (Ni-Mo ₂ C _CB /CFP) 上制备用于析氢反应 (HER)的自支撑 Ni 掺杂 Mo _{2 C。}研究了硝酸镍浓度对Ni掺杂Mo ₂ C@CFP电催化剂的相组成、形貌和电催化HER性能的影响。随着 Ni(NO ₃ ) ₂浓度的不断增加，Mo _2的形貌C逐渐从颗粒状变为花状，提供更大的比表面积和更多的活性位点。_{将镍 (Ni) 掺杂到 Mo 2} C的晶格中大大降低了电催化剂的阻抗并提高了它们的电催化活性。所开发的Mo ₂ C-3 M Ni(NO ₃ ) _{2 /CFP电催化剂表现出高催化活性，在10 mA·cm} ^-2的电流密度下具有56 mV的小过电位。该催化剂具有快速的 HER 动力学，如 27.4 mV·dec ^{-1的非常小的 Tafel 斜率所示}，以及持久的长期稳定性。更高的Ni浓度对电催化性能有不利影响。密度泛函理论（DFT）计算进一步验证了实验结果。Ni掺杂可以降低Mo-H的结合能，促进表面吸附氢（H _ads）的解吸，从而提高Ni掺杂Mo _{2的本征催化活性}C基催化剂。然而，过量的Ni掺杂会抑制电催化剂的催化活性。该工作不仅为简便制备具有高催化活性的非贵金属电催化剂提供了一种简单的策略，而且从理论角度揭示了Ni掺杂浓度对电催化剂HER性能的影响机制。