B, N co-doping graphene nanoribbons as effective oxygen reduction electrocatalyst

Abstract

In this study, a facile method was used to synthesize B, N-co-doped graphene nanoribbons (BN-GNRs), with g-C3N4 as a source of N and boric acid as a source of B, for use as an effective electrocatalyst for the oxygen reduction reaction (ORR). Numerous wavy edges are exposed in GNRs, and these exposed wavy edges provide doping positions for N and B atoms. Compared with single doping of B or N, co-doping of B and N with opposite electronegativity can increase the doping amounts. Thus, the obtained BN-GNRs catalyst has tremendous graphitic- and pyridinic-N active sites, which are beneficial to oxygen adsorption and desorption and to electron mass transfer. Additionally, the interaction between nearby N and B can promote the ORR’s catalytic process and conversion efficiency. BN-GNRs demonstrate strong ORR performance, better selectivity, and stability. Moreover, their half-wave potential can reach 0.852 V in alkaline electrolyte, similar to that for Pt/C. This study shows that BN-GNRs can be employed as an effective metal-free ORR catalyst to replace commercial Pt/C.