Homologous NiCoP@NiFeP heterojunction array achieving high-current hydrogen evolution for alkaline anion exchange membrane electrolyzers

Abstract

Water electrolysis at a high current density (1000 mA cm⁻²-level) with excellent durability is the pivotal issue for a green hydrogen source from experiment to industrialization, requiring catalysts with tunable local charges for favorable water dissociation and fast mass transfer for bubble overflow. Herein, we propose a dual-metallic NiCoP@NiFeP homologous heterojunction array, in which the homologous elements and similar crystal structure will ensure close coupling to improve the accessibility of active interfaces. Meanwhile, the 3D array morphology contributes to the hydrophobic gas surface for guaranteeing the escape of H₂ bubbles at high current density. Benefiting from the harmonic interface charge and mass transport, our constructed electrocatalysts surpass the RuO₂‖Pt/C water splitting activity at 1000 mA cm⁻² @ ∼1.93 V over 100 hours in a real alkaline exchange membrane electrolyzer. Overall, we demonstrate that the multiscale regulation advances the understanding of complex relationships between the atomic interface, catalyst–electrolyte interface, and function in various electrocatalytic processes.