Hierarchical NiFeZn(OH)x/NiZn Electrode Achieving Durable High-Current-Density Oxygen Evolution

Oxygen evolution reaction (OER), a pivotal half-reaction in water splitting and renewable energy conversion, suffers from intrinsically sluggish kinetics, necessitating robust electrocatalysts to lower overpotential and enhance energy efficiency. Nickel-based substrates are particularly appealing due to their ability to form compact and stable oxide layers; however, rationally constructing high-surface-area Ni supports remains a substantial challenge. Here, we develop a synergistic electrodeposition–etching strategy to fabricate clustered NiZn alloy nanowires on Ni foils, followed by mild chemical oxidation. This treatment that induces surface oxidation, promotes Fe incorporation, and drives in situ reconstruction into a nanosheet-like NiFeZn(OH)x catalytic layer. This integrated approach overcomes common issues associated with electrodeposited coatings on NiZn nanowire clusters, including poor hydrophilicity, weak adhesion, and uncontrollable morphology. The optimized NiFeZn(OH)x/NiZn/Ni electrode delivers outstanding OER performance in 1 M KOH, requiring only 229 mV to reach 100 mA cm−2, with a low Tafel slope of 31.6 mV dec−1, and demonstrates exceptional durability over 180 h of continuous operation without performance degradation. The superior catalytic behavior originates from the synergistic interplay between the high-surface-area NiZn nanowire scaffold and the dynamically reconstructed NiFeZn(OH)x active phase. This work provides a generalizable strategy for engineering efficient and durable OER electrodes, offering new design principles for Ni-based alloy supports in advanced electrocatalysis.