Porous graphene doped with Fe/N/S and incorporating Fe3O4 nanoparticles for efficient oxygen reduction

Abstract

The rational construction of a carbon base with a porous structure and incorporating effective dopants is an intriguing and challenging strategy used to develop advanced electrocatalysts for the oxygen reduction reaction (ORR). Herein, we synthesize a novel, efficient electrocatalyst comprised of three-dimensional (3D) porous graphene doped with Fe/N/S and incorporating Fe₃O₄ nanoparticles (Fe₃O₄/FeNSG). We use a melamine formaldehyde resin which plays the dual-functional roles of a soft template and a nitrogen-abundant source. The rational design of the Fe₃O₄/FeNSG-3 with its 3D porous architecture, abundant active sites (Fe–N–C, Fe₃O₄, pyridinic N, C–S–C, et al.), and large surface area (530.5 m² g⁻¹) makes it an efficient electrocatalyst towards ORR. The Fe₃O₄/FeNSG-3 catalyst shows a positive ORR onset potential (0.951 V) and half-wave potential (0.810 V), comparable to those of the commercial Pt/C electrocatalyst in alkaline media. Furthermore, the catalyst exhibits a four-electron transfer pathway, superior methanol tolerance and good stability. This work paves the way for preparing low-cost, active, stable, non-Pt group metal catalysts through regulating the active catalytic sites on 3D graphene with a porous architecture.