Solvent-Assisted Thermal Reduction of Graphite Oxide

Abstract

The thermal behavior of graphite oxide (GO) is essential to study and design GO reduction and functionalizion reaction. We provide a detailed description of the thermal reduction of GO dispersed in solvent (H2O and dimethylformamide (DMF)) at temperatures of 100 and 150 °C, respectively. The thermal stability and structure change of GO during the thermal treatment were characterized using UV−vis spectroscopy, Raman spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). It was found that at temperatures of 100 and 150 °C the carboxylic and carbonyl groups decomposed. GO dispersed in H2O and DMF at temperatures of 100 and 150 °C exhibited increased rates of reduction than in dry condition. Moreover, the reduction rate was found to be highly dependent on the solvent used. At 150 °C, DMF accelerates the GO reduction rate significantly, while dimethyl sulfoxide (DMSO) has less acceleration effect. However, ethylene glycol (EG) reduces the reduction rate compared to dry conditions. The solvent−GO interaction, including polar−polar interaction and hydrogen bonding, was discussed as one possible reason for the solvent-dependent reduction.