▎ 摘　　要

Herein, defect-rich graphene oxide with a crumpled form was fabricated through the fast thermal expansion of H2SO4-intercalated graphite oxide. The fast removal of intercalated H2SO4 molecules and by-product gases result in the formation of crumpled edges, whereas the partial reduction of H2SO4 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.