Three-dimensional N,B-doped graphene aerogel as a synergistically enhanced metal-free catalyst for the oxygen reduction reaction

Abstract

Here, a novel N,B-doped graphene aerogel, abbreviated as N,B-GA, was obtained via a two-step approach and served as a metal-free catalyst for the oxygen reduction reaction (ORR). This two-step method involved a hydrothermal reaction and a pyrolysis procedure, guaranteeing the efficient insertion of the heteroatoms. The resulting three-dimensional (3D) N,B-GA obtained at pyrolysis temperature of 1000 °C exhibited outstanding catalytic activity for the oxygen reduction reaction (ORR), comparable to that of Pt/C. In addition, the catalytic activity of this 3D N,B-GA was obviously better than that of the nitrogen-doped graphene aerogel (N-GA) and boron-doped graphene aerogel (B-GA) in terms of the onset potential, half-wave potential and diffusion limiting current density. The superior catalytic reactivity arises from the synergistic coupling of the B and N dopants within the graphene domains.