不同堆砌层数煤系石墨的拉曼光谱表征及其表面石墨化均匀程度  

Raman Spectroscopic Characterization and Surface Graphitization Degree of Coal-Based Graphite With the Number of Aromatic Layers

作　　者：李焕同[1,2] 曹代勇 邹晓艳[3] 朱志蓉 张卫国 夏炎[4] LI Huan-tong;CAO Dai-yong;ZOU Xiao-yan;ZHU Zhi-rong;ZHANG Wei-guo;XIA Yan(College of Geology and Environment,Xi’an University of Science and Technology,Xi’an 710054,China;Shaanxi Provincial Key Laboratory of Geological Support for Coal Green Exploitation,Xi’an 710054,China;College of Geoscience and Surveying Engineering,China University of Mining and Technology(Beijing),Beijing 100083,China;Coal Geology Survey of Ningxia Hui Autonomous Region,Yinchuan 750011,China)

机构地区：[1]西安科技大学地质与环境学院,陕西西安710054 [2]陕西省煤炭绿色开发地质保障重点实验室,陕西西安710054 [3]中国矿业大学(北京)地球科学与测绘工程学院,北京100083 [4]宁夏回族自治区煤炭地质局,宁夏银川750011

出　　处：《光谱学与光谱分析》2022年第8期2616-2623,共8页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(41502160,41772156);西安科技大学优秀青年科技基金项目(2019YQ2-08);陕西省煤炭绿色开发地质保障重点实验室基础研究计划项目(MTy2019-10)资助。

摘　　要：采用多激发波长(325,405,514,633和785 nm)以及显微拉曼面扫描技术对不同芳香层片平均堆砌层数的煤系石墨及其表面石墨化均匀程度进行表征。结果表明:对无序石墨,石墨微晶的尺寸较小并任意取向,随着平均堆砌度及堆砌层数增加,石墨微晶边缘的拉曼光谱特征显现。在无序结构向有序转化的同时,石墨微晶缺陷逐渐消亡,拉曼光谱一级模中D3、D4峰逐渐不显著或消失,但是其倍频峰均微弱出现,尤其2D1峰强度逐渐增大。将I/I参数的含义进一步引申为缺陷类型及平均定向性,且无烟煤的I/I极大,随着石墨微晶尺寸增大(d<0.3440 nm),至三维有序结构的石墨时I/I最小。在不同激发波长下G峰半高宽总是随着无序度的减小而减小,D1峰和2D1峰等均显示较强的色散效应,各峰强度随激发光能量的增大而增大,在紫外激发下,D1和G峰峰位差显著小于可见光激发。随激发波长的增加,D1峰向着低波数方向移动,2D1峰色散约为D1峰的两倍。高煤级煤石墨化过程中,非定向的芳香碳经历一系列的物理、化学结构演变产生各种中间相态,如残留煤岩显微组分(变镜质组和变惰质组)和新生的石墨组分(热解炭等)共存,因此采用(I-I)/(P)≥0.3,I/I<0.4,A/A<0.45等作为石墨和半石墨的界线,利用平面扫描区域成像来表征样品石墨化的表面均匀程度,取频数分布置信区间≤0.9来综合判定样品表面石墨化度为84.16%~86.40%,平均为85.49%,与利用X射线衍射(XRD)参数估计的石墨化度相当。Comparison of Raman spectra at multi-excitation wavelengths(325,405,514,633 and 785 nm)for coal-based graphite,and evolution of the spectra at 514 nm with the number of aromatic layers were detail studied.Moreover,the Raman mapping test studied the surface defects distribution of coal-based graphite block.The results show disordered graphite has a smaller size and arbitrary orientation than graphite crystallites.With the increase of stacking degree and average stacking layers,the Raman spectrum characteristics of graphite microcrystal edge appear.When the disordered structure of coal-based graphite transforms to order,the defects gradually disappear,and the D3 and D4 peaks in the first-order gradually become invisible or disappear,but the overtone peaks appear weakly,especially as the intensity of the 2 D1 peak increases.Further extending the meaning of I/Iparameter to defect type and average orientation,the I/Iratio of anthracite is the largest.With the increase in crystallite size(d<0.344 nm),the I/Iof 3 D ordered graphite was the smallest.The FWHM of the G peak always decreases with the decrease of disorder at different excitation wavelengths.D1 peak and 2 D1 peak show a strong dispersion effect,and the intensity of each peak grows with the increase of excitation energy.Under UV excitation,the peak position difference of D1 and G peaks is significantly smaller than that under visible light excitation.With the increase of excitation wavelength,the D1 peak moves towards the low wavenumber direction,and the dispersion of the 2 D1 peak is about twice the intensity of the D1 peak.During the graphitization process of high rank coal,the non-oriented aromatic carbon experienced a series of physical and chemical structure evolution to produce various intermediate phases,and the residual coal macerals(vitrinite and inertinite)and new graphite components(pyrolytic carbon,etc.)coexist.(I-I)/(P)≥0.3,I/I<0.4,A/A<0.45 were used as the boundaries of graphite and semi-graphite.The surface uniformity of the sample was charact

关 键 词：拉曼光谱 多激发波长 成像技术 不同堆砌层数 色散 煤系石墨 

分 类 号：TQ533.6[化学工程—煤化学工程]