Trimetallic nanoarchitectonics of FeCoNi catalyst with modulated spin polarization for enhanced oxygen reduction performance

Fe-based catalysts have a good prospect in oxygen reduction reaction (ORR) in fuel cells. However, the catalytic activity of Fe-based catalysts requires further improvement to satisfy the demand in industrial application and the working mechanism is still shrouded in ambiguity. Here, a ferromagnetic catalyst with nitrogen-doped carbon supported FeCoNi alloy was synthesized by impregnation-pyrolysis method. The micromorphology and structure of the catalyst was analyzed by XRD , SEM, TEM, XPS, BET and Raman spectroscopy . The trimetallic catalyst showed high ORR activity in 0.1 M KOH with a half-wave potential of 0.908 V and a limiting current density of 6.153 mA cm −2 , which was superior to 20 % Pt/C. The synergistic effect of FeCoNi alloy regulated the spin polarization and the regulated spin state improved ORR performance by facilitating the adsorption of O 2 molecules and the conversion of the activated intermediates.