An Interlayer Anchored NiMo/MoO2 Electrocatalyst for Hydrogen Evolution Reaction in Anion Exchange Membrane Water Electrolysis at High Current Density

Abstract Noble metal‐free electrodes for anion exchange membrane water electrolysis (AEM‐WE) operating at high current densities are critical for sustainable hydrogen production. However, the massive amount of bubbles resulted in insufficient mass transfer and unevenly distributed local stress, which poses a major challenge in designing an efficient and robust hydrogen evolution catalyst. Herein, a facile chemical corrosion method is developed to synthesize an interlayer‐anchored NiMo/MoO 2 catalyst on a nickel foam (NF) substrate (NiMo/Int/NF) with high hydrogen evolution activity (overpotential of 80.2 ± 3.53 mV) and durability (stable for 5000 h) at 1000 mA cm −2 in 1 m KOH. The interlayer tightly anchors the catalytic layer to the substrate, providing high compressive strength and strong adhesion to mitigate the bubble shock at a high current density. In situ Raman and X‐ray diffraction analyses reveal that the heterostructural catalytic layer can accelerate the hydrogen evolution reaction with increased local pH and high component utilization. Using NiMo/Int/NF as the cathode, the assembled noble metal‐free AEM‐WE device exhibits a low cell voltage of 1.78 V at 1000 mA cm −2 (significantly lower than that of a Pt/C‐catalyzed cell (1.94 V)) while also showing excellent stability for 3000 h.