Evolution of graphene oxide (GO)-based nanohybrid materials with diverse compositions: an overview

The discovery of the 2D nanostructure of graphene was in fact the beginning of a new generation of materials. Graphene itself, its oxidized form graphene oxide (GO), the reduced form of GO (RGO) and their numerous composites are associates of this generation. Out of this spectrum of materials, the development of GO and related hybrid materials has been reviewed in the present article. GO can be functionalized with metals (Ag and Mg) and metal oxides (CuO, MgO, Fe₂O₃, Ag₂O, etc.) nanoparticles (NPs), organic ligands (chitosan and EDTA) and can also be dispersed in different polymeric matrices (PVA, PMMA, PPy, and PAn). All these combinations give rise to nanohybrid materials with improved functionality. An updated report on the chronological development of such nanohybrid materials of diverse nature has been delivered in the present context. Modifications in synthesis methodologies as well as performances and applications of individual materials are addressed accordingly. The functional properties of GO were synergistically modified by photoactive semiconductor NPs; as a result, the GO-MO hybrids acquired excellent photocatalytic ability and were able to degrade a large variety of organic dyes (MB, RhB, MO, MR, etc.) and pathogens. The large surface area of GO was successfully complemented by the NPs so that high and selective adsorption capacity towards metal ions and organic molecules as well as improved charge separation properties could be achieved. As a result, GO-MO hybrids have been considered effective materials in water purification, energy storage and antibacterial applications. GO-MO hybrids with magnetic particles have exhibited selective destruction of cancerous cells and controlled drug release properties, extremely important in the pharmaceutical field. Chitosan and EDTA-modified GO could form 3D network-like structures with strong efficiency in removing heavy metal ions and organic pollutants. GO as a filler enhanced the strength, flexibility and functional properties of common polymers, such as PVA and PVC, to a large extent while, GO-CP composites with polyaniline and polypyrrole are considered suitable for the fabrication of biosensors, supercapacitors, and MEMS as well as efficient photothermal therapy agents. In summary, GO-based hybrids with inorganic and organic counterparts have been designed, the unique properties of which are exploited in versatile fields of applications.