Amorphous NiS deposited on crystalline Co3O4 nanosheets boosting electron transfer for efficient hydrogen evolution

The development of efficient non-precious electrocatalysts for the alkaline hydrogen evolution reaction (HER) is critical for industrial water electrolysis. Herein, an amorphous NiS/crystalline Co 3 O 4 heterostructure (NiS/Co 3 O 4 @CP) is fabricated through a scalable two-step electrodeposition. The heterogeneous interface induces electron transfer from Co 3 O 4 to NiS, creating electron-rich NiS sites for optimized H* adsorption/desorption and high-valence Co 3+ species for accelerated water dissociation. The NiS/Co 3 O 4 @CP catalyst exhibits low overpotential of 60 mV at 10 mA cm −2 in 1 M KOH (25 °C) and maintains durability for 1000 h. Under industrial conditions (80 °C, 6 M KOH), the NiS/Co 3 O 4 @CP also exhibits an overpotential of merely 285 mV at 500 mA cm −2 . In a two-electrode electrolyzer, the NiS/Co 3 O 4 @CP//Ni mesh configuration attains a current density of 500 mA cm −2 at a voltage of merely 1.9 V. This work provides a practical strategy for high-performance HER catalysts.