Multi-scale porous nickel iron oxyhydroxide-based electrodes for highly efficient oxygen evolution reaction

Abstract Alkaline water electrolysis technology for hydrogen production has been successfully commercialized, yet challenges such as insufficient catalytic activity and durability persist. Herein, a novel monolithic electrode architecture (NF/Ni3Fe@NiFe-OOH) featuring a multi-scale hierarchical pore structure was designed to optimize oxygen evolution reaction (OER) kinetics. The electrode comprises three distinct structural components of a macroporous nickel foam framework, a mesoporous nickel-iron alloy nanomelt interlayer, and a microporous nickel-iron oxyhydroxide active layer, which exhibits an overpotential of 210 mV at 100 mA cm-2 and an over 140 h robust durability with 97.2% voltage retention at 50 mA cm-2 (93.2% at 300 mA cm-2). The outstanding OER performance of the sample can be primarily ascribed to the monolithic electrode featuring the multi-scale pore structures, which show significant advantages in facilitating electrolyte diffusion, electron transfer, and efficient bubble dissipation.