Lattice-Oxidation-Driven Efficient OER in FeOOH/NiFeOx Heterointerface Electrocatalyst via Laser-Corrosion Engineering

Abstract

Nickel-iron oxides have emerged as promising candidates to replace precious-metal-based catalysts for the oxygen evolution reaction (OER) owing to their abundance in the Earth's crust and, hence, low cost. However, their inherently poor electrical conductivity and inefficient utilization of active sites severely hinder their large-scale industrial deployment. Herein, we report a novel strategy for the construction of a self-supporting heterostructured electrode (FeOOH/NiFeOx/NFF, where NFF = nickel-iron foam) via a combination of laser ablation and chemical corrosion. The resulting material has a distinctive heterogeneous structure and superhydrophilic and aerophobic surface properties that collectively promote electrolyte infiltration, gas release, and charge transfer. As a result, the FeOOH/NiFeOx/NFF electrode achieves an ultralow overpotential of 208 mV at 10 mA cm-2, along with excellent long-term durability. Mechanistic studies, including in situ spectroscopy and chemical probing, revealed that the exceptional OER performance is governed by a lattice oxidation mechanism. This work provides a viable and scalable pathway for the rational design of high-performance and economically feasible Ni-Fe-based electrocatalysts for industrial alkaline water splitting.