Fabricating Sulfur/Oxygen Co-Doped Crumpled Graphene for High-Performance Oxygen Reduction Reaction Electrocatalysis - Carbon4Energy

Herein, defect-rich graphene oxide with crumpled form was fabricated via 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 while the partial reduction of H2SO4 leads to a large amount of defects and minor S doping (S~0.55 at%). The expanded graphene oxide (CGO) with crumpled form and rich defects was applied as electrode materials for the oxygen reduction reaction (ORR), and 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 ORR; moreover, it may enlighten one type of high-activity sites for ORR: defects on crumpled edges.