Experimental and Theoretical Insights into the Role of Iron in the Rapidly Fabricated Ni/Fe Electrodes for the Oxygen Evolution Reaction

The development of low‐cost electrocatalysts for the oxygen evolution reaction (OER) of water electrolysis is crucial for large‐scale green hydrogen production. NiFe‐based electrocatalysts have garnered significant attention due to their high OER activity; however, the need for a rapid and efficient electrode fabrication method and a clear understanding of the role of Fe in enhancing OER activity remains unresolved. Herein, a highly active NiFe‐based OER electrocatalyst self‐supported on carbon fiber paper (CFP) is developed using a versatile and rapid thermal shock method, requiring only 30 s of heat treatment. The as‐prepared Fe 1 Ni 1 /CFP shows a current density of 493 mA/cm 2 at 1.7 V vs reversible hydrogen electrode (RHE) and a low overpotential of 247 mV at 10 mA/cm 2 , with excellent long‐term durability in alkaline conditions. In situ Raman spectroscopy, pH‐dependance activity test, and electronic structure calculations reveal that Fe not only promotes the oxidation of adjacent Ni but also accelerates the deprotonation of adsorbed –OH groups and stabilizes oxo‐intermediates, thus, displaying both direct and indirect effects and enhancing the overall OER performance. This article provides a foundation for developing cost‐effective electrocatalysts for hydrogen production and other sustainable energy applications while enhancing the understanding of the role of Fe in NiO catalysts.