Engineering Co@Co₃Mo₃N/NPCs heterostructured ultrathin nanosheets electrocatalysts with favorable electronic configuration for boosting alkaline overall water electrolysis

The rational architecture of high-performance electrocatalyst is becoming imperative for H₂ production from electrochemical water splitting. Herein, the pioneering fabrication of Co@Co₃Mo₃N heterojunctions immobilized onto N-doped porous carbon substrates (abbreviated as Co@Co₃Mo₃N/NPCs) are effectuated by a combination of wet-impregnation proceedings of Co,Mo/polyaniline (PANI) precursor and subsequent carbonization/nitridation treatment. This construction can furnish the multitudinous Co@Co₃Mo₃N heterojunction interfacial sites and simultaneously trigger the synergistic effect to encourage the rearrangement of the electronic configuration and the majorization of electrochemically active sites, thus devoting to the comprehensive improvement of the electrocatalytic HER and OER performance. Accordingly, the synthesized Co@Co₃Mo₃N/NPCs electrocatalyst can deliver the exceptional electrocatalytic HER and OER performance with ultra-low overpotentials of 37 mV and 203 mV at a current density of 10 mA cm⁻². Meanwhile, the Co@Co₃Mo₃N/NPC electrocatalysts are assembled into zero-gap alkaline electrolyzer for overall water splitting, which afford an ultra-low voltage of 1.80 V at a current density of 500 mA cm⁻² with ultra-long lifespan of 2400 h. Therefore, this work can provide fire-new perspective and inspiration for synthesizing the art-of-the-state bifunctional electrocatalysts for further commercial application. © 2025 Elsevier B.V.