Synthesis of Fe-doped Co₃O₄ and investigation of the effect of trace Fe in electrolyte on its OER performance

The development of highly active and durable oxygen evolution reaction (OER) electrocatalysts is of great interest in sustainable energy storage and conversion systems. It has been shown that Fe in electrocatalysts is considered to be the most active site, while CoOOH plays the role of a host for electrical conductivity, high surface area and chemical stability. In this paper, Fe-doped Co₃O₄ microsphere films were synthesized on nickel foam substrate (NF) by a simple solvothermal method. The optimized Fe₁Co₁₀O/NF composite electrode exhibits strong OER catalytic performance in 1 mol·L⁻¹ KOH, and achieves a current density of 50 mA·cm⁻² at an ultra-low potential of only 243 mV. It also combines excellent long-term stability. In addition, the present study demonstrated the Fe dependence of the high activity of Co₃O₄ electrocatalysts in Fe-depleted KOH electrolyte.