Low-Cost and Highly Efficient Metal-Free Electrocatalysts for Oxygen Reduction Reaction: Environment-Friendly Three-Dimensional B, N Co-doped Graphene Aerogels

Abstract

Nitrogen (N) and boron (B) co-doped graphene materials have been certified as promising catalyst for oxygen reduction reaction (ORR), since the dual doping of foreign atoms could induce a unique electronic structure in graphene and create a synergistic coupling effect between heteroatoms. However, previously reported B, N co-doped graphene materials suffered from shortcomings such as needing highly toxic precursors or high cost or complex preparation procedures. Herein, one highly efficient metal-free ORR catalyst, three-dimensional graphene aerogels (GAs) co-doped with B and N using economical and environmentally friendly melamine and boric acid as heteroatom precursors, was prepared through a one-step hydrothermal method. The as-prepared microporous B, N co-doped GAs showed excellent electrochemical catalytic performances for ORR under alkaline condition (0.1 M KOH) with a much more positive onset potential (0.994 V vs. RHE) than most of the existing B, N co-doped ones, a dominant four-electron transfer mechanism (n = 3.73 at 0.6 V), as well as excellent stability.