Fluorescent carbon nano-materials with quantum confinement and edge effects have recently piqued attention in a variety of applications, including biological imaging, drug delivery, optoelectronics and sensing. These nano-materials can be synthesized from a variety of carbon-based precursors using both top-down and bottom-up methods. Coal and its derivatives typically include a vast crystalline network and condensed aromatic ring cluster, which can be easily exfoliated by chemical, electrochemical, or physical processes to produce nano-materials. As a result, they are regarded as a low-cost, abundant and efficient carbon source for the fabrication of high-yield nano-materials. Nano-materials synthesized from coal-based precursors have outstanding fluorescence, photostability, biocompatibility and low toxicity, among other properties. Their properties in optical sensors, LED devices, bio-imaging, and photo and electro-catalyst applications have already been investigated. In this review, we have highlighted current developments in the synthesis, structural properties and fluorescence properties of nano-materials synthesized from coal-based precursors.

    Abstract 
    Graphical abstract
    1 Introduction
    2 Precursor of coal-based fluorescent nano-materials and their structure
        2.1 Molecular structure of different coals and their characterization
        2.2 Coal derivatives and their structure
    3 Different synthesis routes of fluorescent nano-materials from coal-based precursors
        3.1 Chemical oxidation method
        3.2 Solvothermal synthesis in non-aqueous solvents
        3.3 Physical exfoliation processes
        3.4 Electrochemical oxidation
    4 Fluorescence properties of nano-materials synthesized from coal-based precursors
    5 Applications of carbon dots synthesized from coal-based precursors
        5.1 Fluorescence applications
        5.2 Other applications: coal-derived CDs in electro and photo-chemical reactions
    6 Conclusions and future prospects
    Acknowledgements 
    References

• Niloy Kundu(Environemnt Research Group, Research and Development Department, Tata Steel Limited)
• Dhrubajyoti Sadhukhan(Environemnt Research Group, Research and Development Department, Tata Steel Limited)
• Supriya Sarkar(Environemnt Research Group, Research and Development Department, Tata Steel Limited)