宁夏碱沟山脱灰无烟煤石墨烯量子点制备与谱学特征  

Preparation and spectroscopic characteristics of coal-based graphene quantum dots from demineralized anthracite in Jiangoushan, Ningxia

作　　者：唐跃刚[1] 李瑞青 樊江涛 马鹏亮 王绍清[1] 罗鹏 郭伟勇 TANG Yuegang;LI Ruiqing;FAN Jiangtao;MA Pengliang;WANG Shaoqing;LUO Peng;GUO Weiyong(College of Geoscience and Surveying Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China;Coal Geological Bureau of Ningxia Hui Autonomous Region,Yinchuan 750011,China)

机构地区：[1]中国矿业大学(北京)地球科学与测绘工程学院,北京100083 [2]宁夏回族自治区煤田地质局,宁夏银川750011

出　　处：《煤炭学报》2022年第12期4278-4289,共12页Journal of China Coal Society

基　　金：宁夏回族自治区重点研发计划资助项目(2021BEG02015);国家自然科学基金资助项目(41872175)。

摘　　要：采用一步化学氧化法,以宁夏碱沟山无烟煤为碳源,探讨了脱灰无烟煤制备石墨烯量子点的可行性。利用X射线衍射分析、拉曼光谱、高分辨透射电镜、X射线光电子能谱和荧光光谱等谱学方法,表征了脱灰无烟煤以及产物石墨烯量子点的化学结构和化学组成。宁夏碱沟山无烟煤及其脱灰样品的碳质量分数较高,分别为94.19%和94.43%,H/C原子比非常低,分别为0.14和0.15。原煤的显微组分以镜质体为主,为81.4%。X射线衍射分析结果表明,脱灰无烟煤的芳香片层直径(L_(a))、堆砌高度(L_(c))及平均堆积层数(Nave)均较好,L_(a)达6.0 nm以上,L_(c)为2.02 nm,平均Nave超过6,具有较高的芳香度,fa为0.89。拉曼光谱分析显示,脱灰无烟煤多环芳香化合物的C—C震动强烈,I_(D)/I_(G)强度比为0.85,G-D峰位差为157.88 cm^(-1),利于石墨烯量子点的制备。研究发现,碱沟山无烟煤通过一步化学氧化法可以制备出尺寸均一、晶型良好、荧光性质稳定的石墨烯量子点,芳香簇尺寸整体较大(8~9 nm),最大直径为12 nm,尺寸在6~10 nm的芳香簇数量达92%;与前驱体煤样相比,脱矿煤样制备的煤基石墨烯量子点具有更小的缺陷度,ID/IG强度比为0.81,G-D峰位差为264.25 cm^(-1)。高分辨透射电镜下煤基石墨烯量子点芳香环排列比较规则,六边形晶体结构可见,具有较好的结晶度。X射线光电子能谱表征表明脱灰无烟煤和所制备的石墨烯量子点的含氧官能团较为单一,主要为C=O(531.3eV),C-O(532.4 eV)和COO—(533.8 eV)。荧光光谱显示煤基石墨烯量子点最大荧光强度处的荧光颜色为蓝色且强度相对较弱,荧光量子产率也比较低,为3.98%。通过与前人研究结果对比,GQDs-JGS的直径明显大于烟煤、褐煤和焦炭制备的石墨烯量子点,散落面积也比其他煤级煤制备的石墨烯量子点要大,GQDs-JGS的芳香环排列也比较规则,不存在部分烟煤基石墨烯量子点中的缺陷结The feasibility of preparing graphene quantum dots(GQDs)from demineralized anthracite was studied by one-step chemical oxidation using the Jiaogoushan anthracite in Ningxia as carbon source. The chemical structure and composition of demineralized anthracite and graphene quantum dots were characterized by X-ray diffraction, Raman spectroscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy and fluorescence spectroscopy. The carbon content of the Jiangoushan anthracite and its demineralized samples is high, 94.19% and 94.43% respectively, and the H/C atomic ratio is very low, 0.14 and 0.15 respectively. The macerals of raw coal are mainly vitrinite, accounting for 81.4%. The results of X-ray diffraction analysis show that the aromatic layer diameter(L_(a)),stacking height(L_(c))and average stacking layer number(Nave)of demineralized anthracite are all good, with L_(a)being more than 6.0 nm, L_(c)being 2.02 nm, Navebeing more than 6 and fabeing 0.89. The Raman spectroscopy analysis shows that the C—C vibration of the demineralized anthracite polycyclic aromatic compounds is strong, the I_(D)/I_(G) value is 0.85,and the G—D value is 157.88 cm^(-1),which is conducive to the preparation of graphene quantum dots. It is found that the graphene quantum dots with uniform size, good crystal form and stable fluorescence properties can be prepared by one-step chemical oxidation from the Jiangoushan anthracite. The overall size of aromatic clusters of GQDs is large(8-9 nm),the maximum diameter is 12 nm, and the number of aromatic clusters with sizes between 6-10 nm reaches 92%. Compared with precursor coal samples, the graphene quantum dots prepared from the demineralized coal samples have smaller defects, with ID/IGvalues of 0.81 and G-D values of 264.25 cm^(-1). Under the high-resolution transmission electron microscope, the aromatic rings of coal-based graphene quantum dots are arranged regularly, the hexagonal crystal structure is visible, and the crystallinity is good. The X-ray pho

关 键 词：无烟煤 煤基石墨烯量子点 一步化学氧化法 谱学特征 荧光 

分 类 号：TQ536.1[化学工程—煤化学工程]