Electrochemical synthesis of multilayer graphene oxide and its application in composite materials

Abstract

An electrochemical method for multilayer graphene oxide production by anodic oxidation of graphite dispersed in sulfuric acid is proposed. The possibility of sequential dispersion of graphite during the electrochemical oxidation and hydrolysis is shown. It was established that the carbon nanostructured materials obtained are prone to agglomeration in aqueous dispersions. After sonication, the particle size of the oxidized graphite was found to significantly decrease with the formation of the multilayer graphene oxide. It was elucidated that the structure of the obtained material consists of multigraphene planes with a thickness of 0.01-0.10 µm, and the pore size is 1-10 µm. The possibility of using the graphene oxide to produce polymer composite materials and composite electrochemical coatings is considered. Regarding the kinetics of the epoxy composition curing, it was observed that the graphene oxide affects the structure formation, which was indicated by an increase in the gel formation duration from 45 to 64 min and curing from 53 to 78 min, with an increase in the maximum curing temperature from 105 to 116 °C. Through the method of thermogravimetric analysis, it was established that the introduction of the graphene oxide reduces the thermal stability of the epoxy composites, but provides increased Vica heat resistance from 100 to 125-158 °C. The width of the passive state area for the nickel-graphene oxide composite electrochemical coating was found to be 1.32-1.40 times higher than that for the pristine nickel coating.