Controllable Synthesis of Fe-Doped NiCo₂ O₄ Nanobelts as Superior Catalysts for Oxygen Evolution Reaction

As one of the promising clean and renewable technologies, water splitting has been a hot topic, especially the half-reaction of oxygen evolution reaction (OER) due to its sluggish and complex kinetics. Hence, Fe-doped NiCo₂ O₄ nanobelts were designed and prepared as catalysts toward OER. By increasing the Fe amount, the catalytic performances of the as-synthesized products went up and then decreased. Profiting from the synergistic effect between Fe atom and NiCo₂ O₄ , all the Fe-NiCo₂ O₄ catalysts exhibited superior catalytic activities to the corresponding NiCo₂ O₄ . In addition, the characteristic nanobelt architecture facilitates the conduction of electrons and the exposure of active sites. With the optimal Fe content, the 9.1 % Fe-NiCo₂ O₄ yielded the smallest overpotential and Tafel slope among the catalysts, distinctly lower than that of RuO₂ .