Synthesis and Characterization of Graphite Intercalation Compounds with Sulfuric Acid

In this work, graphite intercalation compounds (GICs) were synthesized using three different oxidizers: (NH₄)₂ S₂ O₈, K₂ S₂ O₈, and CrO₃ with and without P₂ O₅ as a water-binding agent. Furthermore, the samples obtained were heat-treated at 800^◦ C. Specimens were characterized by optical microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), and scanning electron microscopy (SEM). The correlation between different characteristic parameters of the Raman analysis has shown that the use of CrO₃ results in a much higher structural disorder compared to the products obtained using persulfate oxidizers. Narrowing the correlation set revealed that minimal defect concentration can be reached by using K₂ S₂ O₈, while the use of (NH₄)₂ S₂ O₈ causes a slightly higher concentration of defects. It was also established that the additional use of P₂ O₅ can help to achieve more effective intercalation and has a positive effect on the formation of the stage I GIC phase. After heat treatment, the intercalated products mostly return to a graphite-like structure; however, the samples obtained with CrO₃ stand out with the most significant changes in their surface morphology. Therefore, analysis suggests that GICs obtained using persulfate oxidizers and P₂ O₅ could be a candidate to produce high-quality graphene or graphene oxide.