Cost effective synthesis of carbon nanoparticles and exploring the fluorescence and electrochemical applications

Abstract

Graphene-based materials and composites for sensing are a fascinating field in material science research that is experiencing rapid advancement. But the applications of graphene-based materials were often hampered by their high production cost, low yield, expensive and scarce precursors, harmful processing techniques, etc. Coal is made up of islands of nanometer-sized crystalline carbon domains linked by a 3D network of amorphous aliphatic carbon and polymerized aromatic hydrocarbons that can be extracted using mild oxidizing agents. In this context, the present study reports the successful usage of low-grade coal, lignite as an ideal precursor for the production of carbon nanostructures for various sensing applications. This research is divided into three parts where value addition to coal is being done along with finding solutions to three major environmental issues: fluorescence sensing of copper ion; noninvasive glucose fluorescence sensing; simultaneous electrochemical sensing of heavy newlinemetal ions cadmium and lead. In the first study, carbon nanostructures were synthesized from lignite by a simple, scalable, and economical technique and the as-prepared carbon nanostructures, namely LC1, LC2 and LC3, demonstrated excellent fluorescence characteristics. LC3 exhibited remarkable copper ion sensing with a dual linear range with limits of detection (LOD) as low as 1.32 pM and 2.35 pM, with limits of quantification (LOQ) 4 pM and 7.14 pM respectively. The accuracy of the manufactured sensor was shown by the recovery rates of copper ions, which varied from 98.18% to 101.2% with Relative newlineStandard Deviations (RSDs) below 0.4%. The results are captivating, implying that newlinethese lignite derived carbon nanostructures could be employed to efficiently and newlineeconomically detect low concentrations of copper ions in water. In the second study, carbon nanoribbons and nanosheets with superior fluorescence were synthesized from lignite, using a facile chemical oxidation process.