Influence of nitrogen precursors on the structure, composition, and oxygen reduction reaction performance of dual heteroatom doped carbon nanohorns

Abstract

Heteroatom doped single-walled carbon nanohorns are produced via a facile one-step arc discharge method and used as metal-free catalysts for the oxygen reduction reaction (ORR). The influence of nitrogen-source on the structure and electrocatalytic activity of the nanohorns is studied. Two kinds of N doped carbon nanohorns produced by N₂ or melamine as the N-source, respectively, present similar structure. However, dual-doped carbon nanohorns fabricated from different N-sources possess different structures. NB-dual doped carbon nanohorns synthesized by N₂ would contain the enormous h-BN, which is chemical-inert for ORR. But using melamine as the N-source would prevent this phenomenon and raise the doping of B atoms into the graphene lattice, which lead to the increased ORR catalytic activity. Different with NB-dual doping, NP-dual doping via N₂ would greatly give a rise to the content of N atoms into the materials, and result in the enhanced limited current intensity.