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/MoO₂ 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.