Synthesis of Three‐Dimensional Nitrogen and Sulfur Dual‐Doped Graphene Aerogels as an Efficient Metal‐Free Electrocatalyst for the Oxygen Reduction Reaction

Three‐dimensional (3D) nitrogen and sulfur dual‐doped graphene aerogels (NSGAs) are successfully synthesized by using a rational hydrothermal self‐assembly process with ammonia and sulfur powder as nitrogen and sulfur sources, respectively. Structural characterization, including TEM, HAADF‐STEM, SEM, and XPS indicated that the NSGA catalyst exhibits an interconnected macroporous framework of graphene sheets and tunable contents of N and S. The as‐prepared NSGAs show an excellent electrocatalytic activity for the oxygen reduction reaction, including a highly positive onset potential, high kinetic limiting current density, and fuel tolerance. In particular, the NSGA catalyst reveals a much better long‐term stability than that of Pt/C in alkaline medium.