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

Abstract

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 m 2 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.

Controllable synthesis of two-dimensional tungsten nitride nanosheets as electrocatalysts for oxygen reduction reaction

“…7a shows that the WN catalyst exhibits good electrochemical durability, with current losses of 17.5% after 18,000 s. To provide comparison, Pt/ C was tested under the same conditions, affording obvious activity decay with 27% retention. Because methanol tolerance is another crucial parameter for ORR electrocatalysts [39], the chronoamperometric responses of the WN electrode on the addition of 3 mol L −1 methanol were evaluated in comparison with those of commercial Pt/C (Fig. 7b).…”

A facile strategy for ultrasmall Pt NPs being partially-embedded in N-doped carbon nanosheet structure for efficient electrocatalysis

“…4d, the deconvoluted N 1s contains three peaks positioned at 399.2, 400.9 and 402.4 eV, which can be respectively ascribed to pyrrolic N, graphitic N and oxidized N [31] derived from N elements in pyrrole upon heat treatment. Among them, the pyrrolic and graphitic N species can promote the oxygen reduction via changing the chemical/electronic environment of the neighboring carbon atoms [32][33][34]. Besides, a lower binding energy of 398.5 eV may be attributed to the interaction between Pt and N atoms [15,16].…”

Understanding of the major reactions in solution synthesis of functional nanomaterials

“…Actually, the bottom-up strategy is a common statement in the synthesis of carbon-based materials such as graphene. For example, Sun's group [122] reported the defluorination of polymer can be achieved by the catalysis of CaC2 to fabricate crumpled graphene through bottom-up strategy. Due to the wide range of precursors, the topology, size, composition, structures of nanomaterials can be defined by the right selection and design.…”