N-doped crumpled graphene: bottom-up synthesis and its superior oxygen reduction performance

The crumpled graphene (CrG) was fabricated by applying defluorination of polyvinylidenefluoride (PVDF) on highly curved surface of CaC2 particle through bottom-up synthetic strategy. The limited reaction depth between PVDF and CaC2 leads to the formation of CrG with thin layer (3−6 layer graphene) and reasonable high specific surface area (~324.8 m2 g−1). CrG with N incorporation (N-CrG) was applied as electrode material for reducing oxygen (i.e., oxygen reduction reaction, ORR) in alkaline, showing close onset potential to that of Pt/C and better mass-diffusion behavior. Surprisingly, with increased mass loading of catalysts, N-CrG exhibits steady current increase while Pt/C shows clear current plateau. Meanwhile, the N-CrG sample reveals high cycling stability and tolerance to contaminant, demonstrating its high potential for practical applications. Additionally, the bottom-up synthetic pathway to CrG via polymer dehalogenation on solid alkaline may find more applications which require controlled morphology and thickness of deposited thin graphitic carbon layers.