Scalable Surface Alloying–Dealloying Manufactures Nanoporous Electrodes From Bulk Metals for Ampere‐Level Alkaline Water Electrolysis

ABSTRACT Commercial deployment of alkaline water electrolysis requires electrodes that can sustain ampere‐level current densities while remaining manufacturable at scale; however, most advanced electrocatalysts demonstrated in laboratories lack mechanical robustness and are incompatible with industrial production. Here we report a vapor‐phase surface alloying–dealloying (VPA‐CD) strategy that converts commodity metal sheets directly into bulk‐supported nanoporous electrodes via in situ formation of catalyst layers metallurgically bonded to dense substrates. Applied to Ni‐Mo and Ni‐Fe alloys, this approach yields Mo single‐atom‐doped nanoporous Ni with high hydrogen evolution activity and nanoporous Ni(Fe)/Ni 3 Fe heterostructures with excellent oxygen evolution activity, enabling ampere‐level alkaline electrolysis at low cell voltages. Beyond planar substrates, the method scales to large‐area and patterned architectures that directly integrate flow fields and catalyst layers; the resulting integrated electrolyzer achieves 1.0 A cm −2 at only 1.84 V and remains stable for over 185 h, outperforming commercial benchmarks. These findings establish VPA‐CD as a robust and manufacturable route for engineering nanoporous electrodes, bridging the gap between catalyst discovery and device‐level hydrogen production.