Coal-Derived Carbon Materials: Pathways to Graphene, Carbon Nanotubes, Carbon Quantum Dots, and Nanodiamond for...

Carbon materials have garnered significant interest due to their exceptional physicochemical properties, making them suitable for a wide range of high-end applications. However, the synthesis strategies and large-scale production of these materials remain challenging, primarily due to the limited availability of suitable precursor materials and the complexity of the synthesis processes. Recent advancements have demonstrated that coal, an abundant and inexpensive carbon-rich feedstock, can be effectively utilized to develop high-quality carbon materials, such as graphene and its derivatives, carbon quantum dots, and graphene quantum dots. This review primarily emphasizes the transformation of coal into advanced carbon nanostructures such as graphene, carbon nanotubes, nanodiamonds, and carbon quantum dots, while providing brief coverage of other coal-derived carbons, including graphitic, mesoporous, heteroatom-doped, fibrous, and sheet-like carbon materials obtained from this abundant carbon-rich feedstock. It critically evaluates the advantages and limitations of these techniques and explores their technological applications, particularly in energy storage systems such as batteries and supercapacitors. Furthermore, the review highlights their environmental applications, including biosensing, metal ion detection, photocatalytic dye degradation, CO₂ reduction, and hydrogen generation. By providing a comprehensive overview of the current state of research and future prospects, this review emphasizes the significant potential of coal-derived graphene and related materials for sustainable applications in energy and environmental domains.