Effects of Minerals in Anthracite on the Formation of Coal‐Based Graphene

Abstract

The minerals in raw anthracite significantly limit the preparation of coal‐based graphene. Raw and demineralized anthracites were graphitized and coal‐based graphene was prepared by improved Hummers’ oxidation‐reduction method. The morphologies, crystal structures and spectroscopic characteristics of the products in various stages were characterized by scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy and Raman spectroscopy. The results show that demineralized or not, anthracite can be used to prepare graphene, but the minerals in anthracite physically inhibit the directional development of graphene sheets. And the residual high temperature conversion products of the minerals embedded between graphene sheets will lead to multiple irregular pore defects on the surface of graphene, which will have strongly unfavorable effects on the properties of coal‐based graphene materials. Demineralization of raw anthracite can reduce the defective pores and oxygen‐containing functional groups on the surface of coal‐based graphene and improves its morphology and properties.

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

“…The edges, folds and overlaps within the layers of the products are clearly visible, which is consistent with the morphology characteristics of graphene with few numbers of graphene layers (less than 10 layers) [94]. The graphene sheet has good integrity and no micropores, indicating that demineralization can avoid the microcap caused by the embedding of the products of high-temperature transformation of minerals in coal into the graphene layers [95]. However, in terms of micromorphology, there are still some differences in the structure of coal-based layers prepared from three different raw coals.…”

Extraction, Fractional Structure and Physiological Activities of Fulvic Acid from Yunnan Xundian Lignite

“…The peaks at 3300–3000 cm −1 were mainly caused by the stretching vibrations of unsaturated C−H. The absorption peaks at 2925 and 2850 cm −1 were attributed to aliphatic C−H stretching vibrations [31,33] . There were no obvious peaks in the range of 3000–2800 cm −1 for FA P , indicating that some of the alkyl side chains in YNL may have been broken or oxidised to carboxylic acids during the oxidation process.…”

“…[32] The peaks at 3300-3000 cm À 1 were mainly caused by the stretching vibrations of unsaturated CÀ H. The absorption peaks at 2925 and 2850 cm À 1 were attributed to aliphatic CÀ H stretching vibrations. [31,33] There were no obvious peaks in the range of 3000-2800 cm À 1 for FA P , indicating that some of the alkyl side chains in YNL may have ChemistrySelect been broken or oxidised to carboxylic acids during the oxidation process. FA P contained an absorption peak at 2595 cm À 1 that corresponded to SÀ H stretching vibrations, while there was no obvious peak in this region for YNL.…”

Preliminary Study of Carbonized Bituminous Raw Coal for Supercapacitor Electrode

“…The ID/IG ratio decreases from 2.59 to 2.20 for CBC-700 and CBC-900, respectively, which indicates the creation of a more interconnected hexacyclic carbon structure and a decrease in carbon structure defects with increasing temperature [14]. The presence of defects may originate from the minerals contained in the coal, as Lan et al found that minerals in the coal do not facilitate the graphitization process, instead, they hinder it and result in defects [20]. The CV curve of all samples at a scanning speed of 5 mV s -1 and a voltage range of -0.2 to -1.0 V are depicted in Figure 3 (a).…”