Fabricating Sulfur/Oxygen Co‐Doped Crumpled Graphene for High‐Performance Oxygen Reduction Reaction Electrocatalysis

Herein, defect‐rich graphene oxide with a crumpled form was fabricated through the fast thermal expansion of H 2 SO 4 ‐intercalated graphite oxide. The fast removal of intercalated H 2 SO 4 molecules and by‐product gases result in the formation of crumpled edges, whereas the partial reduction of H 2 SO 4 leads to a large amount of defects and minor S doping (ca. 0.55 at%). The expanded graphene oxide with a crumpled form and rich defects was used as electrode materials for the oxygen reduction reaction (ORR), and a very high ORR performance was observed in 0.1 mol L −1 KOH, exhibiting an onset potential of 0.92 V, a half‐wave potential of 0.83 V, and a roughly 5.68 mA cm −2 limiting current density with catalyst loading of 0.1274 mg cm −2 . Our work provides reliable GO‐based catalyst materials for the ORR; moreover, it will expand the knowledge one type of high‐activity site for the ORR: defects on crumpled edges.