Durable Alkaline Seawater Electrolysis through the Synergistic Effect of Crystalline-Amorphous Interface Coupling of...

Seawater electrolysis offers a sustainable and eco-friendly route for hydrogen production, with advantages of zero carbon emissions and reduced reliance on freshwater. However, the presence of impurity ions, especially Cl^-, imposes strict requirements on electrocatalysts in terms of activity and corrosion resistance, which limits large-scale application. In this work, the crystalline-amorphous (c-a) interface engineering offers a promising pathway to overcome this trade-off. The c-a heterojunction catalyst grown on nickel foam (FcNi-BDC-aNiOOH/NF) is constructed via integrating two-dimensional ferrocene-based metal-organic frameworks (FcNi-BDC) with amorphous nickel oxyhydroxide (aNiOOH). This interface induces dynamic charge redistribution, forming a type-II heterojunction with a built-in electric field that drives directional charge separation and suppresses the electron-hole recombination. This interfacial synergy elevates Ni³⁺ content and optimizes the adsorption free energy of *OOH intermediates (ΔG⁎_OOH = 1.22 eV), while the amorphous phase dynamically passivates surface defects under chloride-rich conditions. As a result, FcNi-BDC-aNiOOH/NF achieves an ultralow oxygen evolution reaction (OER) overpotential of 329 mV at 1000 mA cm^-2 in alkaline seawater, along with exceptional stability (89% retention after 400 h at 500 mA cm^-2) and chloride corrosion resistance (corrosion current density of 26 μA cm^-2). This work elucidates atomic-scale interactions across the c-a interface and provides a universal strategy for developing robust electrocatalysts for large-scale seawater electrolysis and sustainable hydrogen production.