Structural Regulation of NiFe LDH Under Spontaneous Corrosion to Enhance the Oxygen Evolution Properties

Electrochemical water splitting holds promise for sustainable hydrogen production but restricted by the sluggish reaction kinetics at the anodic oxygen evolution. Herein, we present a room-temperature spontaneous corrosion strategy to convert inexpensive iron (Fe) on iron foam substrates into highly active and stable self-supporting nickel iron layered hydroxide (NiFe LDH) catalysts. The corrosion evolution mechanisms are elucidated combining ex-situ scanning electron microscopy (SEM) and X-ray photo electron spectroscopy (XPS) techniques, demonstrating precise control over the concentration of Ni²⁺ and reaction time to achieve controllable micro-structures of NiFe LDH. Taking advantage of the self-supporting morphology and hierarchical micro-/nano- structure, the NiFe LDH with optimized Ni²⁺ concentration and reaction time exhibits significant small overpotentials of 160 mV and 200 mV for the OER at current densities of 10 mA cm^-2 and 100 mA cm^-2 respectively, showcasing excellent OER activities. Furthermore, this catalyst demonstrates superior reaction kinetics, high electrochemical stability, and excellent integral water splitting performance when coupled with a commercial Pt/C cathode. The energy-efficient, cost-effective, and scalable spontaneous corrosion strategy opens new avenues for the development of high-electrochemical-interface catalysts.