Amorphous NiFeCo Oxyhydroxide as a High-Performance Electrocatalyst for Alkaline Oxygen Evolution Reaction

Abstract

Developing efficient and durable electrocatalysts for the oxygen evolution reaction (OER) is critical for advancing water electrolysis technologies. Herein, we report the synthesis of amorphous Co/Mo-alloyed NiFe oxyhydroxides (NiFeCo and NiFeMo) via a sol–gel method. Compared to NiFeMo, the NiFeCo catalyst demonstrates higher OER activity and stability in alkaline media. It achieves a low overpotential of 234 mV at 10 mA/cm² and a Tafel slope of 72 mV/dec. It maintains stable performance for over 100 h in both three-electrode and anion exchange membrane water electrolyzer (AEMWE) configurations. Co alloying induces changes in oxidation states, stabilizing high-valent Ni/Fe species and enhancing charge transfer kinetics, whereas the amorphous structure ensures structural adaptability under prolonged operation. Postoperation characterization reveals retained amorphous integrity despite particle agglomeration, highlighting the synergy between dynamic structural flexibility and electronic optimization. This work provides a promising pathway for designing nonprecious metal-based OER catalysts for industrial water electrolysis applications.