Facile synthesis of preformed mixed nano-carbon structure from low rank coal

Abstract

Coal is a natural energy resource which is mainly used for energy production via combustion. Coal has nanocrystals embedded in it, formed during the coalification process, and is an ideal precursor for nano-carbon dots and diamonds. Herein, we report a facile top-down method to synthesise nanodots and diamonds of the size of 5 nm to 10 nm from three different types of coal by simple chemical leaching. TEM analysis revealed the formation of a mixture of carbon dots, graphene layers, and quantum dots in bituminous coal and sub-bituminous coal. Raman analysis confirmed the existence of synthesized nanodiamond and nano-carbon mixed phase with defects associated with it. It is concluded that graphene quantum dots, nanodiamonds, graphene sheets and carbon dots present in coal can be extracted by simple chemical treatment. These structures can be tuned to photoluminescent material for various optoelectronic applications or energy harvesting devices like super capacitors.

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

“…The disappearance of these peaks in the XRD pattern for WTP‐t after demineralization indicated that the minerals in raw anthracite were effectively removed. After high temperature graphitization, the (002) peaks for G‐WTP and G‐WTP‐t become abnormally sharp because of the disappearance the γ peak (∼20) which is stand for of aliphatic carbon on the edge of aromatic lamellae . However, this peak became more symmetrical with the increase in rank because of the progressive removal of disordered carbon during leaching.…”

Tailoring of low grade coal to fluorescent nanocarbon structures and their potential as a glucose sensor

“…The 1381 cm −1 peak is due to the presence of cyclic carbon groups. The band at 2922 cm −1 arises from the asymmetric vibration of sp 3 bond in CH 2 and CH 3 groups in the hydrocarbon network 11 – 14 . The peak at 2852 cm −1 is ascribed to the overlapping of symmetric vibration of the sp 3 band for CH 3 and CH 2 functional groups.…”

Coal-Based Fluorescent Zero-Dimensional Carbon Nanomaterials: A Short Review

“…56−58 As the rank of coal falls, the dense carbon ring structure of coal-based GQDs loosens the hexagonal structure and the content of sp 2 carbons becomes less, producing a vacancy defect. 59,60 Low-grade (low-quality) coals are becoming increasingly important in light of the declining coal quality around the world. Kumar Thiyagarajan et al 49 synthesized CNs of diverse size and functionalities from low-grade coal lignite following different synthesis techniques, such as refluxing, microwave radiation, and laser ablation in ethylenediamine solution, named as CNP1, CNP2, and CD3, respectively.…”

“…The rank of coal is one of the crucial factors controlling the characteristics of the synthesized CNs. A coal structure study showed that low- and medium-ranked coal comprised more functional groups, side chains, bridge bonds, hydrogen bonds, and loose structures, with few layers and small aromatic rings. − As the rank of coal falls, the dense carbon ring structure of coal-based GQDs loosens the hexagonal structure and the content of sp 2 carbons becomes less, producing a vacancy defect. , Low-grade (low-quality) coals are becoming increasingly important in light of the declining coal quality around the world.…”