Fluorographenes via thermal exfoliation of graphite oxide in SF6, SF4 and MoF6 atmospheres

Abstract

Functionalization of graphene with heteroatoms is of paramount interest. Doping of graphene materials with electron withdrawing groups leads to the opening of the band gap which further results in a change of its electronic and electrochemical properties. Fluorine exhibits the largest electronegativity and thus it is expected that fluorographenes will have significantly different properties from graphene. Fluorinated graphene was prepared by a scalable method using thermal treatments (at different temperatures) or microwave plasma exfoliation of graphite oxides (prepared via chlorate or permanganate routes) in atmospheres containing SF₆, SF₄ or MoF₆ fluorination agents. We characterized the resulting fluorographenes by scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, combustible elemental analysis and cyclic voltammetry. It was observed that with increasing fluorine content the heterogeneous electron transfer rates increased. The scalable fluorination of graphene with relatively low-toxic agents which yields high-performance electrochemical materials should find many applications in electrochemical devices, such as sensors or supercapacitors.