Comparison of thermally and chemically reduced graphene oxides by thermal analysis and Raman spectroscopy

Graphene oxide (GO) is not only an intermediate in top-down graphene preparation, but it is also acknowledged for its convenient application when the hydrophobicity of graphene is a drawback. Its preparation through the wet exfoliation of graphite inevitably leads to a product lacking several of the outstanding features of graphene. The destroyed graphene structure can be at least partially reconstructed by thermal and/or wet chemical reduction. Thermally reduced graphene oxide (TRGO) was obtained by mild heat treatment (300 °C) in argon, while chemically reduced graphene oxide (CRGO) was prepared by using a green reagent, ascorbic acid (AA). The parent GO and the two GO derivatives were compared by thermogravimetric analysis coupled with mass spectroscopy and Raman spectroscopy. Both reductive treatments resulted in enhanced thermal stability and higher C/O ratio. Although the chemical reduction with AA was more efficient in the elimination of the O functionalities, it also resulted in significant fragmentation of the graphene-like platelets.