Molybdenum (Mo) carbide-based electrocatalysts are considered promising candidates to replace Pt-based materials toward the hydrogen evolution reaction (HER). Among different crystal phases of Mo carbides, although Mo₂C exhibits the highest catalytic performance, the activity is still restricted by the strong Mo–H bonding. To weaken the strong Mo–H bonding, creating abundant Mo₂C/MoC interfaces and/or doping a proper amount of electron-rich (such as N and P) dopants into the Mo₂C crystal lattice are effective because of the electron transfer from Mo to surrounding C in carbides and/or N/P dopants. In addition, Mo carbides with well-defined nanostructures, such as one-dimensional nanostructure, are desirable to achieve abundant catalytic active sites. Herein, well-defined N,P-codoped Mo₂C/MoC nanofibers (N,P-Mo_xC NF) were prepared by pyrolysis of phosphomolybdic ([PMo₁₂O₄₀]^3–, PMo₁₂) acid-doped polyaniline nanofibers at 900 °C under an Ar atmosphere, in which the hybrid polymeric precursor was synthesized via a facile interfacial polymerization method. The experimental results indicate that the judicious choice of pyrolysis temperature is essential for creating abundant Mo₂C/MoC interfaces and regulating the N,P-doping level in both Mo carbides and carbon matrixes, which leads to optimized electronic properties for accelerating HER kinetics. As a result, N,P-Mo_xC NF exhibits excellent HER catalytic activity in both acidic and alkaline media. It requires an overpotential of only 107 and 135 mV to reach a current density of 10 mA cm^–2 in 0.5 M H₂SO₄ and 1 M KOH, respectively, which is comparable and even superior to the best of Mo carbide-based electrocatalysts and other noble metal-free electrocatalysts.

中文翻译：

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N，P掺杂的碳化钼纳米纤维可有效制氢

碳化钼（Mo）基电催化剂被认为是有前途的候选材料，可替代基于Pt的材料进行放氢反应（HER）。在Mo碳化物的不同晶相之间，尽管Mo ₂ C表现出最高的催化性能，但其活性仍然受到强Mo-H键的限制。削弱强的Mo-H键，形成丰富的Mo ₂ C /交通部接口和/或掺杂适量富电子（如N和P）掺杂剂进入沫₂C的晶格是有效的，因为电子从Mo转移到碳化物和/或N / P掺杂物中的周围C中。另外，具有良好定义的纳米结构（例如一维纳米结构）的碳化钼对于获得丰富的催化活性位点是理想的。在此，通过磷钼酸盐（[PMo ₁₂ O ₄₀ ] ^3–，PMo _12的热解制备了定义明确的N，P掺杂的Mo ₂ C / MoC纳米纤维（N，P-Mo _x C NF）。）在Ar气氛下于900°C掺杂酸的聚苯胺纳米纤维，其中杂化聚合物前体是通过一种简便的界面聚合方法合成的。实验结果表明，热解温度的明智选择对于在Mo碳化物和碳基体中创建丰富的Mo ₂ C / MoC界面并调节N，P掺杂水平至关重要，这可优化电子性能以加速HER动力学。结果，N，P-Mo _x C NF在酸性和碱性介质中均表现出优异的HER催化活性。它仅需107和135 mV的过电势即可在0.5 MH ₂ SO _4中达到10 mA cm ^–2的电流密度 和1 M KOH，分别相当于甚至优于基于Mo碳化物的电催化剂和其他无贵金属的电催化剂。