Steel Based Precious Group Metal‐Free High‐Performance Electrodes for Alkaline Exchange Membrane Water Electrolysis

The development of platinum‐group‐metal (PGM)‐free electrodes is essential for cost‐effective alkaline water electrolysis. Herein, we report steel‐based electrodes for a fully PGM‐free, ionomer‐free anion exchange membrane water electrolyzer (AEMWE). A Ni layer deposited on stainless steel (ss) was modified via hydrothermal NiMo growth followed by reductive annealing, yielding a hierarchical NiMo@ss catalyst. Structural characterization revealed MoO 2 ‐derived needle‐like structures decorated with metallic Ni and intimate NiMo interfaces. In 0.1 M KOH, the catalyst exhibited an overpotential of −70 mV at −10 mA cm −2 with an apparent Tafel slope of 132 mV dec −1 , demonstrating significantly improved hydrogen evolution reaction kinetics compared to bare stainless steel and electrodeposited Ni. Oxygen evolution reaction (OER) activity of the porous transport layer was enhanced via a simple Ni deposition and anodization procedure, resulting in an overpotential of 284 mV at 10 mA cm −2 . Integration of both electrodes into a PGM‐free AEMWE single cell (5 × 5 cm 2 ) enabled a current density of 1 A cm −2 at 1.92 V in 1 M KOH at 60 °C. The cell further demonstrated stable operation for 60 h under dynamic conditions cycling between 0.1 and 1 A cm −2 . These results highlight the potential of engineered steel‐supported electrodes for scalable noble‐metal‐free hydrogen production.