Heteroatom-doped fullerene C70 as non-metal electrocatalysts for oxygen reduction and oxygen evolution from computational study

Here, we report on computational oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) efficiencies of a series of heteroatom-doped fullerene C70 (X(Cn), with B, N, O or Si as dopant X, replacing five different types of carbon atoms (Cn, n = 1–5) on C70). It is clarified that the X(Cn) is thermodynamically stable. ΔG⁎OH shows a good linear relationship with ΔG⁎OOH and ΔG⁎O. It is worth noting that the ORR overpotential values of N(C1), N(C2), N(C3) and N(C4) are 0.87 V, 0.75 V, 0.67 V and 0.73 V, respectively, which are all greater than Pt (ηORR = 0.45 V), but it shows that ORR can still be catalyzed. Compared with the pristine C70, both B and N doping can reduce OER overpotential value and improve OER performance. In particular, N(C4) (ηOER = 0.55 V) has the closest overpotential to traditional noble metal OER catalysts such as RuO2 (ηOER = 0.42 V), indicating that it can be used as a potential candidate for OER catalysts. According to the volcano plots, the best ORR and OER activities of X(Cn) appear at ΔG⁎OH = 0.56 eV and ΔG⁎O − ΔG⁎OH = 1.78 eV, respectively. This work can provide some clues for the design and discovery of new non-metal carbon-based electrocatalysts.