A Mo-doped amorphous Ni(OH)2 modified Fe3O4 heterostructure catalyst for enhancing hydrogen evolution reaction

The slow kinetics of the cathodic hydrogen evolution reaction (HER) present a significant obstacle for alkaline water electrolysis. Consequently, developing non-precious metal HER catalysts with high activity and stability remains a challenge. This study reports a heterostructure catalyst composed of Mo-doped amorphous Ni(OH) 2 nanosheets modified Fe 3 O 4 crystal nanoparticles (Mo-NiOH@Fe 3 O 4 ). This unique structure exhibits a three-dimensional, coral-like structure, which significantly increases the electrochemically active surface area and exposes more active sites to the electrolyte. The incorporation of Mo-doped amorphous Ni(OH) 2 enriches electron density around Fe atoms, modulating their electronic state and optimizing intrinsic activity. As an alkaline hydrogen evolution catalyst, Mo-NiOH@Fe 3 O 4 requires overpotentials of only 23.7 and 140.6 mV to achieve 10 and 100 mA cm −2 , respectively, demonstrating exceptional catalytic activity. Furthermore, it shows negligible performance degradation at 100 mA cm −2 and maintains stability for over 120 h. This work demonstrates that a heterostructure strategy, integrating Mo-doped amorphous Ni(OH) 2 with Fe 3 O 4 , provides a reasonable route for developing low-cost, high-performance HER catalysts.