Sacrificial Agents Steering the Formation of Active and Stable β ‐Ni(Fe)OOH on NiFe Layered Double Hydroxide for Efficient Oxygen Evolution

The sluggish kinetics of the oxygen evolution reaction (OER) greatly hinder alkaline water electrolysis. NiFe layered double hydroxide (NiFe LDH) is a promising OER pre‐catalyst that anodically reconstructs into the active Ni(Fe)OOH species. However, slow surface reconstruction kinetics and Ni overoxidation toward the γ ‐Ni(Fe)OOH phase severely compromise activity and stability. Herein, we deposit amorphous ZnS onto NiFe LDH (denoted as ZS/LDH) as a sacrificial agent via plasma magnetron sputtering. During electrochemical activation, Lewis acidic Zn 2+ effectively enriches OH − , thereby promoting the surface reconstruction of NiFe LDH. The S 2− undergoes preferential oxidation to SO 4 2− , consuming anodic charge and suppressing Ni overoxidation, directing the formation of a highly active and stable β ‐Ni(Fe)OOH phase. Activated ZS/LDH (A‐ZS/LDH) exhibits enhanced lattice oxygen activity, achieving 207 mV at 10 mA cm −2 and 1200 h stability at 800 mA cm −2 . In an anion exchange membrane water electrolyzer, the A‐ZS/LDH‐based cell requires only 2.05 V to reach 1000 mA cm −2 at 60 °C and operates stably for over 2000 h. Even under high‐frequency start‐stop cycles, it sustains at least 700 h without decay. This work provides a simple sacrificial agent strategy to steer NiFe LDH reconstruction toward the desirable β phase for durable industrial water electrolysis.