氧化石墨的谱学表征及分析

采用改进的Hummers法，通过改变氧化剂用量获得不同氧化程度的氧化石墨，用X射线衍射(XRD)、红外光谱(FTIR)和拉曼光谱(Raman)对产物进行结构和谱学特性的表征，并结合数学分析软件对部分红外和拉曼数据进行分峰拟合。结果表明，石墨经氧化后形成了含有C-OH、-COOH和C-O-C等官能团的石墨层间化合物；氧化剂用量较少时，石墨片层插层氧化不完全，产物的结构中仍存在未被氧化的原石墨周期性结构；随着氧化剂用量的增加，氧化石墨产物的XRD图中原石墨(002)衍射峰逐渐消失，结构中含氧官能团的量逐渐增加，产物的亲水性也逐渐增强；通过对红外光谱的拟合发现，氧化石墨样品在3 198 cm^-1附近有一个红外吸收峰，应归属于C-OH中OH的伸缩振动；随着氧化剂用量的增加，所得氧化石墨产物的拉曼光谱中D峰与G峰的强度积分比R(I_D/I_G)逐渐增大，产物结构中sp²平面域的平均尺寸逐渐减小。

Spectroscopy Characterization and Analysis of Graphite Oxide

The graphite oxide (GO) samples with different degrees of oxidation were prepared from purified natural flake graphite via modified Hummers method controlling the amount of oxidant. The structural and spectral analysis for samples were carried out by using XRD, FTIR, Raman and fitting part of spectral data. The results suggest that graphite is oxidized to graphite intercalation compounds with various oxygen-bearing functional groups such as C-OH, COOH and C-O-C, etc. When the amount of oxidant is low, the crystal layers of graphite could not be intercalated and oxidized completely. Part of the structure for as-obtained products remains the periodic repetition as in graphite along the c-axis direction. With increasing the amount of oxidant, the graphite (002) diffraction peak of products disappears gradually in XRD patterns. The content of oxygen-containing groups in as-obtained products obviously increases with increasing the amount of oxidant, and the hydrophilicity of products is improved. The curve fitting of FTIR data for graphite oxide samples shows an absorption band near 3 198 cm^-1 corresponding to the stretching vibrations of OH in C-OH groups. With the increasing in amount of oxidant, the integral ratio of intensity between D and G bands also increases indicating the decrease in average size of sp² graphitic domains in products.