Preparation and oxygen reduction activity of BN-doped carbons

B-, N- and BN-doped carbons were prepared by the carbonization of poly(furfuryl alcohol) containing either BF3–MeOH complex, melamine or both. Various characterization techniques were conducted in order to understand the controlling factors for the electrocatalytic activity of carbons for oxygen reduction reaction (ORR). Analytical inspections of the obtained XRD profiles, such as the Diamond and the Hirsch methods, revealed that the doping of boron and nitrogen broadened the graphene size distribution; while it did not influence the stacking manner of graphenes. All doped carbons showed reductions in electrical conductivity by the factors of a quarter to a hundredth of the pristine carbons. Development of porosity was observed for the doped carbons. B1s and N1s XPS analyses revealed the presences of B–C bonds and B–N–C moieties in the BN-doped carbons. The oxygen reductive activity, which was assessed by the ORR current density normalized by BET surface area, was increased by the factors of 4–5 for B-doped and N-doped carbons, while a factor of 20 was attained for the BN-doped carbons. The ORR activity of the prepared carbons was found to be controlled by the presence of both the edge-N and B–N–C moieties, which were distinguished by XPS.