演讲题目:Synthesis of Graphene Derivatives from Fluorographene
内容摘要
Graphene covalent derivatization represents a vivid approach to module its properties, e.g., electronic structure, water dispersability etc., and enhances its application potential. However, a direct derivatization of graphene is impractical due to its low reactivity. Fluorographene is a stoichiometric and well-defined graphene derivative. Being perfluorinated hydrocarbon, fluorographene was considered unreactive. A few examples document that fluorographene can be converted to graphene derivatives at rather mild conditions. For instance, the as prepared thiofluorographene exhibits suitable electrochemical sensing properties.
Covalent functionalization of graphene significantly modulates its physical chemical properties and broadens its application potential.1,2 In 2010, the stoichiometric derivative of graphene named fluorographene was prepared.3-5 Fluorographene electronic properties considerably differ from graphene, because it has a wide band-gap (~8 eV)6-8 and is considered the thinnest insulator.4 It can be prepared by fluorination of graphene, mechanical or chemical exfoliation of graphite fluoride, which is industrially used lubricant. The preparation of flurographene dispersions can be easily up-scaled, e.g., following the procedures suggested for graphene by Coleman and coworkers.9 Flurographene (CF)n is a perfluorinated hydrocarbon and therefore it was considered unreactive.4 It is also thermally stable material up to 300 °C.4 The low reactivity of fluorographene was questioned by early experiments, which shown that at higher temperature (180 °C) it could react with KI and produced low quality graphene.5 This reaction was, however, considered a curiosity. Very recently it was shown that fluorographene reacted at very mild conditions as electrophile with many nucleophiles.10-13 Namely the reaction with NaSH leading to preparation of thiofluorographene should be highlighted, because thiofluorographene can be effectively used for electrochemical sensing applications.13 These results indicate that fluorographene is a very promising material for large-scale preparation of dispersions of various graphene derivatives with designed properties. Further prospects and very recent advances in fluorographene derivations will also be discussed.
Acknowledgement: Support from grants ERC (683024) by EU; LO1305 by MEYS of CZ and Neuron fund are gratefully acknowledged.