Heterostructure engineering of Ni-Co@Co₂Mo₃O₈ nanosheets with pollen biomass-derived carbon frameworks for accelerating alkaline overall water electrolysis

The design of high-performance bifunctional electrocatalysts is critical for H₂ generation through electrochemical water electrolysis. Here, the Ni heteroatoms-decorated Co@Co₂Mo₃O₈ heterojunctions hybridized with rape pollen (RP)-derived nitrogen-doped porous carbon frameworks (Ni-Co@Co₂Mo₃O₈/CNPs) were innovatively fabricated by wet-impregnation treatment and thermal annealing. This designed nanostructure can provide effective electronic promoters and innumerable heterointerface sites while simultaneously enabling extremely strong interactions among these components, not only reinforcing the nano-structural durability and facilitating the interfacial electron transformation, but also arousing the synergistic effect to actuate the rearrangement of electron configuration and ameliorate the adsorption capacity of intermediates, ultimately achieving comprehensive enhancement of electrocatalytic performance. On these grounds, a fine-tuned Ni-Co@Co₂Mo₃O₈/CNPs possesses the excellent electrocatalytic performance, featuring ultra-low overpotentials of 49 and 194 mV HER and OER at 10 mA cm⁻² respectively. Meantime, when Ni-Co@Co₂Mo₃O₈/CNPs is applied in an H-type electrolyzer, it can obtain an exceptionally low voltage of 1.45 V at 10 mA cm⁻², coupled with remarkable durability of 200 h. In a zero-gap alkaline electrolyzer, it can achieve an ultra-low voltage of 1.80 V at 500 mA cm⁻², accompanied by an ultra-long operational lifespan of 2500 h. © 2026 Elsevier B.V.