Structural and electronic structure investigations on sonication based synthesized graphene oxide and reduced-graphene oxide nano-sheets

Abstract

In the present study, we applied a sonication based method to achieve graphene oxide (GO) and reduced graphene oxide (r-GO) nano-structures. X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM) and x-ray absorption near edge structure (XANES) spectroscopy measurements were applied to characterize the samples. XRD, TEM and Raman results demonstrate significant crystalline nature of GO nano sheets. On the other hand, the r-GO sample shows poor crystallinity with a large number of lattice defects. The FTIR spectrum conveys the attachment of significant oxygen-containing functional groups in GO sample. The detachment of oxygen function groups from the r-GO sample, under the reduction process, is also confirmed by the FTIR spectra. Local electronic structure investigations, from the C K-edge XANES of GO and r-GO nano sheets, convey the lowering of 1s -> pi* and 1s -> sigma* transitions and lesser sp(2) character of the carbon ring. The O K-edge XANES spectra have shown the accumulation of C = O sigma*, C-O sigma* and O-H sigma* states at the basal plane of GO and elimination of such functional groups in the r-GO samples and convey controlled tailoring of the functionalities of GO and r-GO nano sheets.