Crafting Hierarchical Porous NiZn Electrode for Alkaline Hydrogen Evolution Reaction

ABSTRACT Metal doping and the construction of porous structures are widely recognized as the key to construct high‐performance hydrogen evolution reaction (HER) catalysts. Herein, a simple and rapid preparation strategy for a NiZn electrode with a hierarchical porous structure is reported. A convenient one‐step electrodeposition method utilizes bubble templates to construct a macro‐scale gully‐like structure while introducing Zn dopant. Subsequently, alkali etching of Zn builds a mesoporous microstructure. This hierarchical porous structure not only significantly increases the active surface area of the electrode, which provides abundant active sites, but also facilitates the escape process of the product. Furthermore, Zn doping regulates the electronic structure of Ni, which optimizes the synergistic interaction between Ni(OH) ₂ and Ni, while inducing strong interfacial electronic interactions to accelerate the charge transfer process during water splitting. Consequently, the obtained NiZn _0.4 electrode just requires a low overpotential of 138 mV at a current density of 100 mA cm ⁻² . When integrated into an alkaline water electrolyzer (ALK), it achieves a current density of 0.5 A cm ⁻² at a cell voltage of 1.85 V and displays robust stability at 100 mA cm ⁻² over 200 h, which underscores its potential for practical applications.