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

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)/Ni₃Fe 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.