Enhancing the Electrochemical Oxygen Evolution Activity of Co–Fe Spinel Oxides via Low‐Temperature Fluorine Doping

Abstract The electrochemical oxygen evolution reaction (OER) is an important anodic reaction of the water electrolysis to generate green hydrogen. In this regard, spinel oxides have attracted significant attention due to their higher OER activity in alkaline electrolytes and the range of metals that can be used in such oxides. This study attempted to enhance the OER activities of Co–Fe spinel oxides through low‐temperature fluorine doping approach. F‐doping was found not to significantly affect the morphology of the catalysts but did slightly reduce the valence state of Co without affecting that of Fe. OER activity measurements demonstrated that F‐doping improved OER activity, particularly in catalysts containing both Fe and Co, by reducing the overpotential and enhancing kinetics. These results suggest that modifications of the electronic structures of spinel oxides through F‐doping are a promising approach to developing highly active OER catalysts composed of spinel oxides.