Graphene oxide/Iron III oxide (GO: Fe2O3) nanocomposites (NCs) have been topical in recent times owing to the enhanced properties they exhibit. GO acting as a graphene derivative has demonstrated superior features as obtainable in a graphene sheet. Furthermore, the attachment of oxygen functional groups at its basal and edge planes of graphene has allowed for easy metal/oxide functionalization for improved properties harvesting. Fe2O3 nanoparticles (NPs) on the other hand have polymorphic property enabling the degeneracy of Fe2O3 in different phases, thereby resulting in different physical and crystalline properties when used to functionalize GO. The properties of GO: Fe2O3 have been applied to supercapacitor energy harvesting, Li-ion batteries, and biomedicine. The enhanced properties are attributed to the adsorption and electronic structure properties of Fe atoms. In this review, the various synthesis used in the preparation of reduced/graphene oxide: Fe2O3 is discussed. As indicated in the considered literature, the XPS analysis suggests electronic bond interactions between C–C, C–O, C–Fe and Fe–C. The available report on UPS measurements further suggests the formation of mixed states emanating from  and  bonds. The discussed reports further suggest that the various applications based on the harvesting of electronic, electrical, and magnetic properties are due to the ionic and exchange interactions between the different orbital states of carbon, oxygen and iron. The challenges and future prospects of the synthesis and application of GO/Fe2O3 are examined. Graphical abstract showing the process of exfoliation, reduction and functionalization of graphite to produce reduced graphene oxide (rGO).

Graphene oxide: Fe2O3 nanocomposite: synthesis, properties, and applications
    Abstract
        Graphical abstract
    1 Introduction
    2 Synthesis methods
        2.1 Hydrothermal technique
        2.2 Microwave-assistedirradiation synthesis method
        2.3 Spray drying method
        2.4 Thermal decomposition method
    3 Properties of GO: Fe2O3 NCs
        3.1 Electronic properties of GO: Fe2O3 NCs
            3.1.1 Raman spectroscopy
            3.1.2 X-ray photoelectron spectroscopy
            3.1.3 Ultraviolet photoelectron spectroscopy
            3.1.4 X-ray absorption near edge structure
        3.2 Electrical properties of GO: Fe2O3 NCs
        3.3 Thermal stability properties of GO: Fe2O3 NCs
        3.4 Magnetic properties of GO: Fe2O3 NCs
    4 Application of GOrGO: Fe2O3 NCs
        4.1 Supercapacitors
        4.2 Rechargeable batteries
        4.3 Magnetic resonance imaging contrast agents and targeted drug delivery
        4.4 Anti-corrosive coatings
        4.5 GO: Fe2O3 composite for the treatment of contaminated water with heavy metals and dyes
        4.6 Photocatalysis for water splitting and purification applications
    5 Outlook, disadvantages and prospects of GO: Fe2O3 nanocomposites
    6 Conclusions
    References

• David O. Idisi(Fort Hare Institute of Technology, University of Fort Hare, Private Bag X1314, Alice 5700, South Africa)
• Uyiosa Osagie Aigbe(Department of Mathematics and Physics, Cape Peninsula University of Technology, Cape Town, South Africa)
• Chinedu C. Ahia(Fort Hare Institute of Technology, University of Fort Hare, Private Bag X1314, Alice 5700, South Africa)
• Edson L. Meyer(Fort Hare Institute of Technology, University of Fort Hare, Private Bag X1314, Alice 5700, South Africa)