Facile synthesis of defect-rich Fe-N-C hybrid from fullerene/ferrotetraphenylporphyrin as efficient oxygen reduction electrocatalyst for Zn-air battery

Exploring remarkable oxygen reduction reaction (ORR) electrocatalysts for regenerative fuel cells and metal-air batteries is highly essential. Herein, a novel non-noble metal-based heterogeneous electrocatalyst with rich defects were successfully synthesized by liquid-liquid interfacial precipitation (LLIP) of fullerene (C60) and ferrotetraphenylporphyrin (FeTPP) followed by one step pyrolysis. The obtained product annealed at 700°C (C60/FeTPP-700), when employed as ORR electrocatalyst, revealed a positive half-wave potential (E1/2) of 0.877 V vs. reversible hydrogen electrode (RHE), which was superior to that of the commercial 25% Pt/C. Delightfully, the assembled Zn-air battery (ZAB) using C60/FeTPP-700 as an air-electrode catalyst exhibited a high power density of 153 mW/cm2, specific capacity of 668 mAh/g and long-term cycling stability for more than 250 h. Experimental results proved that the excellent electrocatalytic ORR activity of C60/FeTPP-700 would attribute to the synergistic effect between FeNxsites, Fe3C/Fe nanoparticles and the structure defects. This work provides a feasible and simple method to prepare non-noble metal-based ORR electrocatalysts for the application of energy storage and conversion.