Synergistic electronic and water microenvironment regulation via metallic heterointerfaces for anion exchange membrane water electrolysis

The pursuit of high-performance and robust hydrogen evolution reaction (HER) catalysts tailored for anion exchange membrane water electrolysis (AEMWE) is crucial yet profoundly challenging. Here, we engineer a metallic heterointerface by embedding ultrafine Os nanoparticles within vertically aligned NiCo alloy nanoflower arrays anchored on the macroporous Ni foam scaffold (Os@NiCo/NF), achieving synergistic modulation of interfacial electronic states and water microenvironment. In-situ Raman spectroscopy unveils that the Os-NiCo interface dynamically restructures interfacial water networks, transitioning from tetrahedrally coordinated water to free water, which enhances reactant accessibility and accelerates water dissociation. Theoretical calculations demonstrate that metal-support interactions induce charge redistribution, synergistically reducing the water dissociation barrier while optimizing hydrogen adsorption energy. When Os@NiCo/NF is deployed as the cathode in the AEMWE device, it achieves an industrial-relevant current density of 1.4 A cm −2 at a voltage of 2 V, while consistently maintaining steady operation at a current density of 500 mA cm −2 for 120 h. This work presents a novel perspective on synergistic interface engineering, unlocking the efficiency potential of the next generation electrocatalysts.