Unveiling the Role of Electrocatalysts Activation for Iron-Doped Ni Oxyhydroxide in Enhancing the Catalytic Performance of Oxygen Evolution Reaction

Abstract

Water electrolysis using renewable electricity is a promising strategy for high-purity hydrogen production. To realize the practical application of water electrolysis, an electrocatalyst with high redox properties and low cost is essential for enhancing the sluggish oxygen evolution reaction. Herein, we fabricated Fe-doped nickel oxalate (Fe-NiC₂O₄) directly grown on nickel (Ni) foam as an efficient electrocatalyst for the alkaline oxygen evolution reaction using a facile one-step hydrothermal method. Fe-NiC₂O₄ served as a precursor for obtaining highly active Fe-doped Ni oxyhydroxide (Fe-NiOOH) via in situ electrochemical oxidation. Consequently, 0.75Fe-NiOOH was demonstrated to be the optimal electrocatalyst, exhibiting outstanding oxygen evolution reaction activity with a low overpotential of 220 mV at a current density of 100 mA cm⁻² and a Tafel slope of 20.5 mV dec⁻¹. Furthermore, Fe-NiOOH maintained its oxygen evolution reaction activity without performance decay during long-term electrochemical measurements, owing to the phase transformation from nickel oxyhydroxide (NiOOH) to γ-NiOOH (gamma nickel oxyhydroxide). These performances significantly surpass those of recently reported transition-metal-based electrocatalysts.