High-dispersion/N-doping FeCo@NC with abundant active sites for high-activity oxygen reduction catalysts

The agglomeration phenomenon of metals in transition metal-based carbon catalysts has been one of the major reasons hindering their replacement of commercial Pt/C. Its self-aggregation phenomenon greatly limits the number of active sites and reactivity, which affects the catalytic performance. To overcome this issue, this work prepared a high N-doped carbon structure catalyst coated with high-dispersion FeCo/Fe 3 C nanoparticles. This was achieved by utilizing the advantages of the Prussian blue analogs (PBA) metal framework structure to suppress the self-aggregation of metals, thereby achieving high dispersion. Additionally, the introduction of melamine compensated for the nitrogen loss caused by the carbonization of PBA, thus increasing the nitrogen doping content. The experimental results show that when the calcination temperature is 850 °C and the mass ratio of melamine to FeCo PBA is 5, the half-wave potential (E 1/2 ) of the FeCo@NC catalyst prepared can reach 0.857 V, and the current intensity of FeCo@NC catalyst can maintain 97.12 % during 40,000 s stability test, which is much higher than that of commercial Pt/C. Moreover, the prepared FeCoNC@-850-5 and commercial Pt/C catalysts were used as cathode catalysts for Zn-air batteries (ZAB), and FeCoNC@-850-5 had higher open-circuit voltage (OCV), power density, and specific capacity. These findings demonstrate that the catalyst possesses excellent catalytic activity and promising application prospects, providing a new perspective for the design of efficient oxygen reduction catalysts based on the coupling of bimetallic alloys and N-doped carbon materials.