Effects of Changing the Amount of Oxidizing Agents on the Structural Properties of Graphene Oxide and its Dispersion Stability in an Aqueous Medium

We prepared graphene oxide (GO) using the Staudenmaier preparation procedure. The amount of oxidizing agents was varied to obtain a different amount of oxygen functionality on the GO surface. The difference in the amount of oxidizing agents during preparation produced GO samples with the interlayer distance 8.7 angstrom and 11.7 angstrom. The interlayer distance increased due to the heavily functionalized GO surface. The products were analyzed using X-ray diffraction, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, energy-dispersive spectroscopy, Raman, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction, and zeta potential measurements. We determined that increasing the oxidizing agents could have a profound effect in rapidly driving the reaction to completion by increasing the rate of reaction. The prepared GO samples exhibited differing degrees of thermal decomposition behavior. Since the number of oxygen functional groups on the GO surface is directly linked to the hydrophilic properties of the GO, it could be successfully tuned by introducing changes in the amount of reactants. This technique directly influenced the GO's aqueous dispersion behavior. This work explores the ways to have better control over the extent of oxygen functionalization in the GO surface. GO with a greater amount of oxygen functionality can be useful in the synthesis of composite materials, and it can also potentially enhance the electronic storage capabilities in capacitors for energy storage, as well as other applications.