Immobilizing Low‐Cost Metal Nitrides in Electrochemically Reconstructed Platinum Group Metal (PGM)‐Free Oxy‐(Hydroxides) Surface for Exceptional OER Kinetics in Anion Exchange Membrane Water Electrolysis

Abstract A highly efficient and platinum group metal (PGM)‐free oxygen evolution reaction (OER) electrode is developed by immobilizing Ni 3 N particles on the electrochemically reconstructed amorphous oxy‐hydroxides surface, resulting in a twofold higher industrial relevance current density of 1 A cm geo −2 at an ultra‐small overpotential η( O 2 ) of 271 mV, with a high turnover frequency of 2.53 s −1 , high Faradic efficiency of 99.6 % and exceptional OER stability of 1000 h in continuous electrolysis. Such a unique amorphous‐crystalline interface with enriched active sites greatly facilitates electron transport and OER kinetics at the electrode‐electrolyte interface. Further, combined with an efficient PGM‐free cathode (MoNi 4 /MoO 2 @Ni), this electrode demonstrates a current density of 685 mA cm geo −2 at 1.85 V cell at 70 °C in an anion exchange membrane water electrolyzer (AEMWE) operated with ultra‐pure water‐electrolyte. These findings highlight the design of highly‐efficient oxygen‐evolving catalysts and significant advancement in the practical implementation of AEMWEs for grid‐scale hydrogen production.