Improving the catalytic performance of nickel-iron oxide to oxygen evolution reaction by refining its particles with the assistance of ionic liquid

In this work, an electrocatalyst (IL-NiO center dot Fe2O3) to oxygen reduction reaction (OER) was fabricated by hydrothermal method with the assistance of ionic liquid 1-ethyl-3-methylimidazolium nitrate ([EMIm]NO3). The catalyst was characterized by scanning electron microscopy, X-ray diffraction, surface area, particle size analyzer, and Raman spectroscopy. The catalytic performance of IL-NiO center dot Fe2O3 to OER was evaluated by electrochemical linear sweep voltammetry, chronopotentiometry, and electrochemical impedance spectroscopy. The results show that ionic liquid [EMIm]NO3 can refine the particles of IL-NiO center dot Fe2O3 to decrease its particle size and increase the specific surface area and pore volume. IL-NiO center dot Fe2O3 also has a smaller charge transfer resistance and reaction resistance in electrocatalytic process to OER, which is beneficial to enhance the performance of catalyst. By the catalysis of IL-NiO center dot Fe2O3, OER can work at a greater current density and a lower overpotential.