Mechanochemically driven solid-state Diels–Alder reaction of graphite into graphene nanoplatelets

Abstract

A mechanochemically driven solid-state Diels-Alder reaction is demonstrated via dry ball-milling graphite as the diene in the presence of maleic anhydride or maleimide as the dienophile. On the basis of various characterizations, the Diels-Alder adducts are edge-selectively functionalized and subsequently delaminated into graphene nanoplatelets.

Functionalization of Graphite with the Diels–Alder Reaction to Fabricate Metal‐Free Electrocatalysts for Highly Efficient Hydrogen Evolution Reaction

“…Figure features the schematic synthesis of the MI‐GnPs and MI‐EGnPs by DA reaction and the HER process. The DA reaction was performed by [4 + 2] cycloaddition between graphite flake and MI, which serve as dienophile and diene, respectively ,. In the present study, different procedures were used to the functionalization of surface and edges graphite by solvent and ball‐milling mechanochemical approaches, respectively.…”

“…After ball‐milling, MI‐EGnPs reduced to smaller grain sizes (0.4 ‐ 0.7 μm). The changes in the morphology of MI‐EGnPs confirm the edge‐selectively functionalized due to the mechanochemically reaction . While, the MI‐GnPs exhibit a layer‐like morphology with little aggregating, which increase the layer spacing of graphite sheets due to effective functionalization onto the surface and edge graphene.…”

“…However, the intensity ratio of the D peak to the G peak (I D /I G ) indicated size reduction and edge distortion in the carbon framework. The I D /I G ratio of MI‐EGnPs was about 1.5, which was higher than pristine graphite; this confirm that the [4 + 2] cycloadditions presumably occurred more at the edges of structure and introduced of sp 3 defects by mechanical exfoliation . The MI‐GnPs show the strong G band at 1576 cm −1 without a detectable D band.…”

“…The peaks around at 3400 and 1200 cm −1 belong to the characteristic of O−H and C−O stretching, respectively. However, the successful functionalization process was approved by the emergence of functional groups in the FT‐IR spectra …”

CHAPTER 2. Carbon–Carbon Bond Forming by Ball Milling

“…57 In situ generated active carbon species (carboradicals, carboanions and -cations), produced by mechanochemical breaking of graphitic carbon-carbon bonds, reacted with the dienophile to yield edge-selectively functionalized graphene nanoplatelets. This reaction was executed in a planetary ball mill at 500 min À1 for 48 h under argon atmosphere.…”