Despite enormous popularity of graphene oxide (GO) several open questions remain regarding the structure and properties of this material. One of those questions is the role of a graphite precursor on the properties of GO product. In this study, we investigate the oxidation process and the structure of GO products, made from the four different graphite precursors: synthetic graphite, two natural flaky graphites, and expanded graphite. The highest rate of the oxidation reaction was registered for the small particle size synthetic graphite. Thermal expansion of natural flaky graphite did not significantly affect the rate of the reaction. The nature of the graphite precursor does not notably affect the chemical composition of the synthesized GO products. However, it affects stability of respective aqueous dispersions. The solutions of the three GO samples, prepared from the natural graphite sources demonstrate excellent stability due to complete exfoliation of GO to single-atomic-layer sheets. GO from synthetic graphite forms unstable dispersions due to the presence of numerous multi-layered particles. This, in turn, is explained by the presence of not fully graphitized, amorphous inclusions in synthetic graphite. Our observations suggest that synthetic graphite should not be used as GO precursor when the ability to completely exfoliate and the stability of dispersions are critical for intended applications.

Revealing the effect of graphite source on the properties of synthesized graphene oxide
    Abstract
    1 Introduction
    2 Material and methods
        2.1 Materials
        2.2 Synthesis of GO samples
        2.3 Characterization
    3 Results and discussion
        3.1 Reaction time and elemental analysis
        3.2 TGA​
        3.3 XRD
        3.4 FTIR spectroscopy
        3.5 SEM
        3.6 Stability of GO dispersions in water
    4 Conclusions
    Acknowledgements 
    References

• Yulia Ioni(Kurnakov Institute of General and Inorganic Chemistry of Russian Academy of Science, Leninskii Pr. 31, Moscow 119991, Russian Federation) Corresponding author
• Timur Khamidullin(Laboratory for Advanced Carbon Nanomaterials, Chemical Institute, Kazan Federal University, Kremlyovskaya str. 18, Kazan 420008, Russian Federation)
• Ivan Sapkov(Kurnakov Institute of General and Inorganic Chemistry of Russian Academy of Science, Leninskii Pr. 31, Moscow 119991, Russian Federation, Faculty of Physics, M.V. Lomonosov Moscow State University, Leninskie Gory 1‑2, Moscow 119991, Russian Federation)
• Vasiliy Brysko(Laboratory for Advanced Carbon Nanomaterials, Chemical Institute, Kazan Federal University, Kremlyovskaya str. 18, Kazan 420008, Russian Federation)
• Ayrat M. Dimiev(Laboratory for Advanced Carbon Nanomaterials, Chemical Institute, Kazan Federal University, Kremlyovskaya str. 18, Kazan 420008, Russian Federation)