【摘要】 为研究煤的接触变质作用对煤基石墨烯量子点性质的影响，以形成于深成变质、区域岩浆变质的煤为对比，采用氧化剥离法进行煤基石墨烯量子点的制备，并利用X射线衍射(XRD)、拉曼光谱(Raman)、透射电镜(TEM)、X射线光电子能谱(XPS)、荧光光谱(PL)对原煤及制备产物的结构进行分析。实验结果表明，随煤级升高，脱灰煤的结构缺陷减少，芳香片层逐渐增大，晶体结构向有序化方向进行。以煤为碳源制备而成的量子点，粒度均一性良好，并随煤级升高粒径有更大的趋势。碳元素以C—C/C—H形式为主，氧主要存在于碳氧官能团中，C∶O≤7∶3,且氧含量随煤级升高而升高。在紫外光(λ=297 nm)的照射下，样品散发蓝色荧光，且在煤级较低时荧光强度较大，并随煤级升高逐渐降低。相较于深成变质、区域岩浆变质形成的煤，接触变质作用形成的煤，产物具有更多的COO—结构，而C==O键含量降低；荧光强度在煤级较低时的上升趋势更为明显，并在高阶烟煤达到最大；受接触变质作用影响的煤，具有更加规则的石墨化结构。更多还原

【Abstract】 Objectives:Coal is a kind of sedimentary rock seriously affected by geological action,and its properties will have a profound impact on the properties of carbon-based materials.In order to explore the influence of contact metamorphism on the properties of coal-based graphene quantum dots,coal formed in plutonic metamorphism and regional magmatic metamorphism was selected for comparison to explore the difference in properties of prepared products.Meththods:Preparation of coal-based graphene quantum clots by oxidative exfoliation method.Graphene quantum dots were obtained from deashed coal by ultrasonic,acid bathing,neutralization,dialysis and drying processes.The structures of raw coal and prepared products were analyzed by X-ray diffraction(XRD),Raman spectroscopy(Raman),Transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS) and Fluorescence spectroscopy(PL).Results:With the increase of coal rank,the structural defects of(leashing coal decrease,the aromatic structure increases gradually,and the crystal structure proceeds in the direction of ordering.The particle size uniformity of quantum dots prepared with coal as carbon source is good,and the particle size tends to be larger with the increase of coal rank.Carbon element is mainly in the form of C—C/C—H,and oxygen mainly exists in carbon and oxygen functional groups,C:O≤7:3,and the oxygen content increases with the increase of coal rank.In ultraviolet light(λ=Under the irradiation of 297 nm),the sample emits blue fluorescence,and the fluorescence intensity is higher in lower rank coal and gradually decreases with coal rank increasing.Compared with coal formed by plutonic metamorphism and regional magmatic metamorphism,the thermal coal formed by contact metamorphism has more COO—structure,and the content of C=O bond decreases;The rising trend of fluorescence intensity is more obvious when the coal rank is lower,and reaches the maximum in high rank bituminous coal;The coal affected by contact metamorphism has a more regular graphitization structure.Conclusions:Coal formed by contact metamorphism can be used to prepare graphene quantum dots,and the prepared products have higher aromaticity,greater ductility and smaller interlayer spacing,and show higher graphitization degree.At the same time,the prepared graphene quantum dots have good uniformity,larger size than other metamorphism,and are arranged in a more regular and orderly aromatic structure.With the deepening of metamorphism,the C—C ratio of the prepared products gradually decreases,and more 0 elements are doped into the quantum dot structure.更多还原