Despite great efforts over the past decade, rational design of bifunctional electrocatalysts with low cost and high efficiency still remains a challenge to achieve industrial water splitting. Herein, we synthesized the nickel-molybdenum nanorod array catalyst supported on NF (NMO@NM/MO) by a two-step process of hydrothermal and reductive annealing. Partial reduction of the NiMoO₄ induces the structural reconstruction and formation of the Ni₄Mo/MoO₂ heterostructure on oxygen vacancy enriched nanorod, which bring out sufficient active sites, large specific surface area and favorable interfacial charge transfer. Thanks to the unique core–shell structure with the heterostructured Ni₄Mo/MoO₂ surface and defect-rich NiMoO₄ core, the obtained electrocatalyst shows greatly improved hydrogen evolution reaction (HER) activity with an ultralow overpotential of 63 mV at 100 mA cm⁻² (vs. 314 mV for the NiMoO₄). Density function theory calculations reveal that the construction of the Ni₄Mo/MoO₂ heterostructure effectively accelerates H₂O dissociation kinetics, while the defective NiMoO₄ facilitates H* adsorption/desorption. Moreover, the heterostructure catalyst also displays excellent oxygen evolution reaction (OER) performance with the low overpotential of 274 mV at 100 mA cm⁻². When coupling HER and OER by using NMO@NM/MO as both the cathode and anode, the alkaline electrolyzer delivers a current density of 10 mA cm⁻² at only 1.50 V as well as good robustness. The synergistic effect of the hetero-interface and the defect engineering endows the electrocatalyst with excellent bifunctional catalytic activity for HER and OER. This work may provide a route for rational design of heterostructure electrocatalysts with multiple active components.

尽管经过过去十年的努力，合理设计低成本、高效率的双功能电催化剂仍然是实现工业水分解的挑战。在此，我们通过水热和还原退火两步法合成了纳米纤维负载的镍钼纳米棒阵列催化剂（NMO@NM/MO）。NiMoO ₄的部分还原诱导了富氧空位纳米棒上的结构重构和Ni ₄ Mo/MoO _{2异质结构的形成，从而带来了足够的活性位点、大的比表面积和有利的界面电荷转移。由于具有异质结构Ni 4} Mo/MoO ₂表面和富含缺陷的NiMoO ₄核的独特核壳结构，所获得的电催化剂表现出极大改善的析氢反应（HER）活性，在100 mA cm下具有63 mV的超低过电势^-2（相对于 NiMoO ₄的 314 mV ）。_{密度函数理论计算表明，Ni 4} Mo/MoO ₂异质结构的构建有效地加速了H ₂ O的解离动力学，而缺陷的NiMoO ₄则有利于H * 的吸附/解吸。此外，该异质结构催化剂还表现出优异的析氧反应（OER）性能，在100 mA cm ^-2下具有274 mV的低过电势。^{当使用NMO@NM/MO作为阴极和阳极耦合HER和OER时，碱性电解槽在仅1.50 V的电压下即可提供10 mA cm -2}的电流密度，并且具有良好的鲁棒性。异质界面和缺陷工程的协同作用赋予电催化剂优异的HER和OER双功能催化活性。这项工作可能为合理设计具有多种活性组分的异质结构电催化剂提供一条途径。