Sulfonated graphene oxide with improved ionic performances

Graphene oxide is well known as a new kind of functional materials because of its super-high specie surface area, mechanical strength, as well as excellent amphipathicity. In this article, graphene oxide was further sulfonated via substitution reaction with diazo salt of sulfanilic in order to endow graphene oxide with better ion exchange capacity and proton conductivity. The microstructure and morphology of the obtained sulfonated graphene oxide were characterized by X-ray diffraction (XRD), Raman spectra, and TEM, while the sulfonation of graphene oxide was confirmed by energy-dispersive X-ray (EDX) and Fourier transform infrared spectroscopy (FTIR) spectra. As expected, ion exchange capacity and proton conductivity of sulfonated graphene oxide increased by about 0.589 and 33.6 times than those of graphene oxide, respectively.