Quasi-<i>in situ</i> redeposition-enabled stabilization of NiFe-based (oxy)hydroxides under high OER current density

Abstract

NiFe-based (oxy)hydroxides are promising oxygen evolution reaction (OER) catalysts but suffer from severe Fe dissolution under operational conditions, rapidly resulting in a significant drop in activity. Here, we report a quasi-in situ redeposition strategy enabled by Ce doping to realize rapid capture and deposition of Fe species on the surface of NiFeOOH. During the OER process, dissolved Ce ions, owing to their large ionic radius and strong electrostatic attraction, enhance OH− concentration at the solid–liquid interface, accelerating Fe redeposition and suppressing Fe leaching into the electrolyte. This significantly enhances activity and durability under high-current density. The optimized Ce-NiFeOOH catalyst delivers an overpotential of 294 mV at 1000 mA cm−2 and maintains excellent stability at 500 mA cm−2. This strategy offers a feasible direction to design highly stable transition-metal-based (oxy)hydroxides for the OER.