A new method for controlling the synthesis of graphite oxide: The effect of hydrogen peroxide

Abstract

The role of hydrogen peroxide in the formation of graphite oxide (GO) synthesized using the modified Hummers’ method was investigated. The main parameter to be investigated is the volume of H₂O₂ (32 %) added at the end of the synthesis, ranging from 53 to 316 mL per 5 g of graphite. Scanning electron microscopy, X-ray diffraction, Raman spectroscopy, energy-dispersive X-ray spectroscopy, Boehm titration, and X-ray photoelectron spectroscopy were used for the investigation of GO samples. It was found that the increase in H₂O₂ volume from 53 mL induced a growth in the concentration of carboxylic groups, approaching a maximum at 210 mL (3.04 ± 0.122 mmol/g), and further increases in this volume led to a monotonous decrease in concentration down to 315 mL (2.39 ± 0.062 mmol/g). The exposure of graphite in the reaction mixture after adding H₂O₂ showed a decrease in oxygen concentration in GO, accompanied by a decrease in the concentrations of carboxylic and lactone groups, along with a growth in concentration of phenolic groups (according to Boehm titration).