LAUSR

Oxidation of graphite is the first important step for the industrial scale preparation of graphene by top-down method using graphite as a starting material. In this study, graphite was oxidized by economically viable and environmentally friendly thermal oxidation method. Pristine graphite (PG) was heated in a furnace under atmospheric condition between 200 and 1000 °C for specific time (5–20 min) and the samples were characterized through thermogravimetry analysis, X-ray photoelectron spectroscopy, Raman spectroscopy, X-ray diffraction, atomic force microscopy (AFM) and finally crystal simulation and molecular dynamic (MD) simulation were performed. The results exhibited that significant oxidation of PG took place when it was heated between 200 and 600 °C for shorter time (≤ 5 min), but partial reduction in oxidized graphite happened when heated for longer time (≥ 10 min) at same temperature. However, reduction of PG took place when it was heated between 800 and 1000 °C. The extent of oxidation was the maximum (17%) when graphite was heated at 400 °C for 5 min. Van der walls energy for graphite and oxygen system determined from MD simulation also found to be the maximum at 400 °C causing higher degree of oxidation. Finally, plausible mechanism of oxidation and reduction of graphite at different temperature and time was discussed based on experimental and simulation results.