Effects of the oxygenic groups on the mechanism of fluorination of graphene oxide and its structure.

A facile way to prepare fluorinated graphene (FG) with a high fluorine content and controllable structure is important to achieve its full potential application. In this work, it was found that the fluorine to carbon (F/C) ratio of fluorinated graphene oxide (FGO) was nearly twice as much as that of fluorinated chemically reduced graphene oxide (FCrGO) after fluorination at the same temperature. Concerning the detailed effects of oxygenic groups on the fluorination and structure of fluorinated graphene (FG), graphene oxides with different oxygen contents were fluorinated under the same conditions. It was shown that oxygenic groups promote the fluorination reaction by activating the surrounding aromatic regions and taking part in the substitution reaction with fluorine radicals, among which, hydroxyls and carbonyls tend to be replaced by fluorine atoms. Moreover, the fluorination mainly occurs at the edges and defects of graphene sheets with a low oxygen content, while the highly oxidized graphene sheets are fluorinated both at the edges and basal planes simultaneously. This indicates that the quantity and location of the C-F bonds in FGO can be controlled by adjusting the species and content of oxygenic groups in the precursor graphene oxide.