Study on the microstructure of the symbiosis of coal-based graphene and coal-based graphene quantum dots: preparation and characterization

Abstract

Coal-based graphene sheets (GS) and coal-based graphene quantum dots (GQDs) are usually prepared separately. In this paper, symbiosis of coal-based GS and coal-based GQDs was successfully prepared with our proposed preparation method by using three raw coals with different reflectance (collected from Qinshui coalfield, Shanxi Province) as carbon sources. The results showed that coal-based GS and coal-based GQDs can exist stably in the symbiosis and are distributed in different layers, and the GQDs are freely distributed between layers of GS. The average number of GS (N ave) in the three symbiosis is about 7 and the average interlayer spacing (d 002) is about 0.3887 nm. The average diameter of GQDs in the three symbiosis is about 4.255 nm and the average d 002 is about 0.230 nm. The average N ave of the three symbiosis was about 3 and the average d 002 is about 0.361 nm. The morphology and crystal parameters of symbiosis is more similar to that of graphene, the elements are only carbon and oxygen. In the prepared symbiosis, the higher the reflectance of raw coal, the smoother the lattice skeleton and the less vortex-layer structure of GS, and the larger the diameter and the denser the six membered ring of GQDs. The C and O functional groups of the prepared symbionts are similar. The higher the reflectance of coal, the higher the content of C–C/C=C. Under ultraviolet light, the prepared products all emit blue, and the higher the reflectance of coal, the higher the ultraviolet absorption, and the stronger the fluorescence intensity.

Chemical Structure Evolution of Thermally Altered Coal during the Preparation of Coal-Based Graphene and Division of Thermally Altered Zone: Based on FTIR and Raman

“…1−3 As a carbon source with large reserves and a rich aromatic structure, coal is an ideal raw material for the preparation of coalbased carbon materials. 4,5 At present, research on coal-based graphene is in the exploratory stage, and most of the studies focus on the influence of coal rank, macerals, and minerals on coal-based graphene. 6−9 However, there is little research on the influence of metamorphism on coal-based graphene.…”

“…As a high-value-added carbon material with excellent properties, coal-based graphene is an important industrial chain of the coal industry and has great application potential in many fields. − As a carbon source with large reserves and a rich aromatic structure, coal is an ideal raw material for the preparation of coal-based carbon materials. , …”

Effects of Minerals Type and Content on the Synthetic Graphitization of Coal: Insights from the Mixture of Minerals and Anthracite with Varied Rank

“…Furthermore, in discussions of the effect of organic matter in coal on the structure of coal-based graphite, many studies have tries to remove the minerals in coal with acid and alkali (such as concentrated hydrochloric acid and hydrofluoric acid) to mitigate the effects of the minerals [32][33][34][35]. However, it is not possible to completely remove the minerals from coal via a chemical method, and the excessive acid, alkali, and waste liquid are not friendly to the environment.…”