Synthesis and characterization of carbon dots from coconut shell by optimizing the hydrothermal carbonization process
K. Abinaya, S.K. Rajkishore, A. Lakshmanan, R. Anandham, P. Dhananchezhiyan, M. Praghadeesh
Abstract
Coconut shell is one of the major agro-by products vis-a-vis agro-waste generated by coconut processing units. At present, Coconut shells are largely utilized as feed material for thermal power conversion by various allied industrial sectors, which is a highly energy inefficient and ecologically unfriendly process. The present study aimed to generate activated carbon dots/ carbon nanomaterials with a wide range of potential applications through a relatively less energy dependant hydrothermal carbonization process. Hydrothermal carbonization is a one-step, simple, low cost and environmental friendly approach to obtain carbon dots. The findings demonstrate that coconut shells when subjected to hydrothermal carbonization process at 250ᵒC for 6 h produced uniform-sized, stable, negatively charged and amorphous forms of carbon dots. Characterization of carbon dots using High-Resolution Transmission Electron Microscopy (HR-TEM), Scanning Electron Microscopy (SEM), Selected Area Electron Diffraction (SAED), X- ray Diffractometer (XRD), UV- Visible Spectroscopy, Particle Size Analyzer (PSA), Brunauer–Emmett-Teller (BET) Analyzer, Elemental Dispersive X-ray (EDX) analyzer and Fourier Transform Infrared Spectroscopy (FTIR) had conclusively confirmed the versatility of the carbon dots generation process and were able to achieve stable 2 nm-sized, spherical shaped carbon dots with numerous downstream applications. The study will help the conversion of agro-waste coconut shells into useful bio-based fluorescent carbon dots.