Buckyball C60/Fe-N4 superstructured electrodes for efficient oxygen reduction reaction

Fullerene-based materials are promising electrodes for various electrochemistry applications due to their specific electronic properties, easy functionalization, and self-assembly capability. To achieve good catalytic performance, fullerenes are always converted into unfolded fullerenes in the derived carbon electrodes. However, the potential of fullerene-based electrodes with closed-cage fullerenes, which may further reflect the fullerene's uniqueness, still needs to be explored. Here, we fabricated a new fullerene C60-based electrode (C60-FePc_500) by the co-assembly of C60 and iron-phthalocyanine (FePc) and pyrolysis under the low temperature of 500 degrees C for the oxygen reduction reaction (ORR). C60-FePc_500 could maintain the buckyball structure of C60 with the binding of active Fe-N4 derived from FePc. For the first time, this buckyball C60/Fe-N4 superstructured electrode with complete C60s exhibited higher catalytic ORR performance than the unfolded C60s electrodes from 900 degrees C heat treatment (C60-FePc_900). Based on the structural analysis and the simulations, the excellent catalytic activity of C60-FePc_500 is estimated due to the improvement of the closed-cage C60s on the electronic density states of Fe-N4 catalytic sites. This work may bring new insights into understanding the driven mechanism of fullerenes and the development of superior fullerene-based electrodes for electrocatalytic processes.