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-doping graphene nanoribbons (BN-GNRs) with g-C3N4 as a source of N, and boric acid as a source of B, used as an effective electrocatalyst for ORR. A lot of edge defects are exposed in GNRs with wavy edges, and these flaws provide N and B atoms with doping sites. 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-N and pyridinic-N active sites, which are beneficial to oxygen adsorption and desorption and electron mass transfer. Additionally, the interaction between nearby N and B can promote the ORR's catalytic process and conversion efficiency. BN-GNRs demonstrates a strong ORR performance, better selectivity and stability. The half-wave potential can reach 0.852 V in alkaline electrolyte, it is similar to the Pt/C. This study shows that BN-GNRs can be employed as an effective metal-free ORR catalyst to replace the commercial Pt/C.