Two-step synthesis of boron and nitrogen co-doped graphene as a synergistically enhanced catalyst for the oxygen reduction reaction

Abstract

A two-step strategy was developed to co-dope graphene with boron and nitrogen as a metal-free catalyst for the oxygen reduction reaction (ORR). This method involved a hydrothermal reaction and a thermal annealing procedure, which guaranteed the efficient insertion of heteroatoms, producing B and N co-doped graphene frameworks (BNG) with high ORR reactivity, good stability and tolerance for methanol in alkaline media. The onset potential of BNG was −0.17 V, and the current density reached −5.5 mA cm⁻² at the voltage of −0.8 V during the RDE test (vs. Ag/AgCl, rotating rate = 1600 rpm, scanning rate = 10 mV s⁻¹), comparable to a high-performance commercial Pt/C catalyst. It is believed that the superior catalytic reactivity arises from the synergistic coupling of the B and N dopants on the graphene domains.