Nanostructured FeNi₃ Incorporated with Carbon Doped with Multiple Nonmetal Elements for the Oxygen Evolution Reaction

The sluggish oxygen evolution reaction (OER) through water electrolysis is still challenging. Herein, a facile approach to fabricate highly efficient nanostructured FeNi₃ incorporated on carbon doped with multiple nonmetal elements (FeNi₃ /M-C) was prepared by annealing an in situ polymerized metal complex from economical precursors. The temperature dependence of the structure and the catalytic performance for the OER was probed. The best pyrolysis temperature was 800 °C, at which the fabricated material exhibited the highest catalytic performance for the OER. Specifically, an overpotential as low as 246 mV (no IR correction) afforded 10 mA cm^-2 with a low Tafel slope of 40 mV dec^-1 , exceeding that of the best noble-metal catalyst IrO₂ and other similar Fe-Ni alloys. High catalytic efficiency and anticorrosion ability towards the OER were displayed in terms of high specific surface area, rapid kinetics, high stability, and specific activity. The excellent performance was correlated to the structure and the modest graphitization degree of carbon and an appropriate ratio between graphitic and pyridinic N atoms and the synergistic effect between the Fe-Ni alloy active sites and the conducting carbon doped with multiple nonmetal elements. Moreover, as a powder catalyst, it could be applied in a real polymer electrolyte membrane electrolyzer. These results are helpful for understanding the improved catalytic activity and the promotion of the catalytic efficiency of the Fe-Ni alloy materials for the OER.