How to determine functional groups in graphene oxide?
Answers
Answer:
Michio Inagaki, Feiyu Kang, in Materials Science and Engineering of Carbon: Fundamentals (Second Edition), 2014
d Graphene oxide
Graphene oxide is a single-layer sheet of graphite oxide, which was proposed one and a half century ago. In recent years, graphene oxide has attracted great concern mainly because it is a potential starting material for the mass production of graphene. Chemistry of graphene oxide has been reviewed [355].
Graphene oxide can be a semiconductor or insulator, depending on the degree of oxidation, and their electronic and optical properties can be tuned in large scope. The controllable optical and electronic properties enable graphene oxide to be used in many fields. The major concern about graphene oxide is mainly focused on its chemical structure [355–357], electronic properties [358,359], reduction reaction [360,361] and chemical functionalization [362,363].
The structure of graphene oxide is still unclear due to its complicated non-stoichiometric nature. There are different kinds of oxygen species and bondings to carbon in graphene layer, such as epoxy, hydroxyl, carbonyl, carboxylic groups
The electronic properties of graphene oxide mainly depend on the oxidation level and chemical composition; it can be tailored by removal or addition of certain oxygen groups to adjust the proportion of sp2 and sp3 carbon [364,365]. Graphene oxide is easily converted into graphene, as explained above. The application fields of graphene oxide are mainly focused on sensor [366] and drug delivery [367]. With a large amount of functional groups, graphene oxide can react with many chemical groups and can be easily modified to improve its functionalities and create new functionalities.