Electronic structures of graphene oxide (GO) and hydro-thermally reduced graphene oxides (rGOs) processed at low temperatures (120–180°C) 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 sp 2 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 α XES spectra shows that the overlapping π and π* orbitals in rGOs and GO are similar to that of highly ordered pyrolytic graphite (HOPG), which has no band-gap. C K α RIXS spectra provide evidence that thermal reduction changes the density of states (DOSs) that is generated in the π-region and/or in the gap between the π and π* levels of the GO and rGOs. Two-dimensional C K α RIXS mapping of the heavy reduction of rGOs further confirms that the residual oxygen and/or oxygen-containing functional groups modify the π and σ 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.
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机译：利用X射线吸收近边缘结构（XANES），X射线发射光谱学（XANES）研究了在低温（120–180°C）下加工的氧化石墨烯（GO）和水热还原氧化石墨烯（rGOs）的电子结构。 XES）和共振非弹性X射线散射（RIXS）。 rGO的C K边缘XANES光谱表明，热还原可恢复C = C sp 2 键，并除去GO中的一些氧和羟基，从而引发了碳质物种的演化。 CK边缘XANES和K α XES光谱的结合表明，rGOs和GO中的π和π*轨道重叠，类似于无带的高阶热解石墨（HOPG）。间隙。 CK α RIXS光谱提供的证据表明热还原改变了GO和rGO的π区域和/或π和π*能级之间的间隙中产生的态（DOS）的密度。 。 rGOs大量还原的二维C K α RIXS映射进一步证实，残留的氧和/或含氧官能团会修饰π和σ特征，这些特征会被光子激发能分散。 K点附近的色散行为近似线性，不同于HOPG中观察到的类似抛物线的色散。
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