Improved heterogeneous electron transfer kinetics of fluorinated graphene derivatives

Abstract

Though graphitic carbons are commercially available for various electrochemical processes, their performance is limited in terms of various electrochemical activities. Recent experiments on layered carbon materials, such as graphene, demonstrated an augmented performance of these systems in all electrochemical activities due to their unique electronic properties, enhanced surface area, structure and chemical stabilities. Moreover, flexibility in controlling electronic, as well as electrochemical activities by heteroatom doping brings further leverage in their practical use. Here, we study the electron transfer kinetics of fluorinated graphene derivatives, known as fluorinated graphene oxide (FGO) and its reduced form, RFGO. Enhanced electron transfer kinetics (heterogeneous electron transfer (HET)) is observed from these fluorinated systems in comparison to their undoped systems such as graphene oxide (GO) and reduced GO. A detailed study has been conducted using standard redox probes and biomolecules revealing the enhanced electro-catalytic activities of FGO and RFGO, and electron transfer rates are simulated theoretically. This study reveals that fluorine not only induces defects in graphitic lattice leading to an enhanced HET process but also can modify the electronic structure of graphene surface.

Fluorographene: Synthesis and sensing applications

“…19 But, in another report the HET rates obtained for RFGO (functional groups reduced fluorinated GO, chemically modified FG) was found to be ;3.2 Â 10 À3 cm/s. 24 This value was found to be higher than that of report for Cl-TRGO (2.52 Â 10 À3 cm/s). Hence, atomic weight of the doped element in graphene also plays an important role in determining the resultant HET rates, and hence its applications in sensing.…”

“…It is also reported that the highly electronegative fluorine bound to the graphene scaffold would affect the surface properties and sensing performance for various analytes and biomarkers. 24 It is also found that low fluorinated graphene exhibits excellent sensing properties for all the studied biomolecules, outperforming pristine graphene, thus opening new possibilities for biosensing applications. The low F content will augment the electron transfer from electrode to bio-molecule or vice versa, will not affect much the electrical conductivity of graphene and also wetting properties of graphene.…”

“…The schematic shows the enhancement in the electron transfer properties while using FGO for a reversible redox probe. 24 the C-F makes THF more interactive in FG. This corroborates with the experimental findings given in Fig.…”

“…25 Various attempts were made for the development of different halogenated graphenes'. 20,24 Out of numerous methods, post-treatment of graphene in halogen atmosphere, thermal annealing of graphene oxide in the presence of iodine, UV irradiation of a few-layer graphene in Cl/Br solutions, Cl plasma treatment of graphene, thermal exfoliation and reduction of graphite oxide in halogen atmosphere etc. are to name a few.…”

p‐Element‐Doped Graphene: Heteroatoms for Electrochemical Enhancement

“…[34] Following this research, fluorinated graphenes showed similar trends. [35,36] Fluorinated graphite oxides showed a significant drop in the inherent electrochemical reduction peak. [37] This peak is typical for the electrochemical reduction of graphene oxide and it is ascribed to reduction of carbonyl, epoxy, and aldehyde groups.…”