Publication Date:
2014-04-11
Description:
Electronic structures of graphene oxide (GO) and hydro-thermally reduced graphene oxides (rGOs) processed at low temperatures (120180C) were studied using X-ray absorption near-edge structure (XANES), X-ray emission spectroscopy (XES) and resonant inelastic X-ray scattering (RIXS). C K-edge XANES spectra of rGOs reveal that thermal reduction restores C = C sp2 bonds and removes some of the oxygen and hydroxyl groups of GO, which initiates the evolution of carbonaceous species. The combination of C K-edge XANES and K XES spectra shows that the overlapping and * orbitals in rGOs and GO are similar to that of highly ordered pyrolytic graphite (HOPG), which has no band-gap. C K RIXS spectra provide evidence that thermal reduction changes the density of states (DOSs) that is generated in the -region and/or in the gap between the and * levels of the GO and rGOs. Two-dimensional C K RIXS mapping of the heavy reduction of rGOs further confirms that the residual oxygen and/or oxygen-containing functional groups modify the and features, which are dispersed by the photon excitation energy. The dispersion behavior near the K point is approximately linear and differs from the parabolic-like dispersion observed in HOPG. Scientific Reports 4 doi: 10.1038/srep04525
Electronic ISSN:
2045-2322
Topics:
Natural Sciences in General
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