Solvent-Assisted Thermal Reduction of Graphite Oxide

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 degrees 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 degrees C the carboxylic and carbonyl groups decomposed. GO dispersed in H2O and DMF at temperatures of 100 and 150 degrees 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 degrees 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.