Preparation and spectroscopic characterization of coal-based graphene from anthracite in Xiaofalu,Yunnan,China

In order to study the preparation and spectroscopic characterization of coal-based graphene from an-thracite in Xiaofalu,a coal-based graphene was prepared by modified Hummers redox method,and the chemical structures of raw coal and process products were characterized by transmission electron microscope ( TEM), X-ray diffraction (XRD),Raman spectrum and Fourier transform infrared spectroscopy ( FT-IR). The results show that high tempera- ture graphitization significantly improves the microcrystalline structure of Xiaofalu anthracite,in-creases the crystallite size,and the average aromatic layer number can reach 54. 84,which is conducive to the formation of graphene oxide. The oxidation reaction produces a large number of oxygen functional groups,which increases the defect degree of coal- based graphene oxide (ID1 / IG = 2. 06),and the layer spacing is up to 0. 790 nm. The oxygen functional groups on the surface of graphene are greatly reduced,the defect degree decreases to 1. 58,and the order degree of aromatic carbon increases,the coal-based graphene is successfully obtained. Under the transmission electron microscopy,it is found that the lattice fringes of Xiaofalu anthracite coal are mostly non-directionally curved,and the stacking between layers is thicker. The coal-based graphene has a transparent thin layer,and the surface contains more warpage. Linear lattice stripes can be observed at the edges,and the number of layers reaches 3 to 5 layers. The oxygen-containing functional groups of Xiaofalu anthracite are mainly phenol,alcohol,ether and ester. Five kinds of hydroxyl groups are detected. The oxygen functional groups on the surface of coal-based graphene oxide are ether and / or epoxide,self-associated hy- droxyl group and OH—ether bond / cyclic hydroxyl group is dominant,and the remaining small amount of oxygen-con- taining functional groups in the coal-based graphene after reduction is mainly ether and / or epoxide,which is stable and difficult to be eliminated.