Biogenic synthesis of highly fluorescent carbon dots using Azadirachta indica leaves: An eco-friendly approach with enhanced photocatalytic degradation efficiency towards Malachite green.

A simpler and efficient method has been developed for the green synthesis of highly fluorescent carbon dots (CDs) from Azadirachta Indica leaves. The surface morphology of developed CDs has shown the existence of spherical particles in the size range of 3-8 nm with superior biocompatibility and high quantum yield value i.e. 42.3%. The particles exhibited a highly fluorescent and crystalline nature along with a bandgap value of 4.02 eV. The prepared CDs served as a factorial design for the sensing and degradation of Malachite green among other dyes. The main perspective of the current finding is that the designed catalyst exhibits excellent sensing results towards Malachite green with a limit of detection i.e. 0.144 μM in the concentration range of 0-50 μM. Moreover, the UV triggered results of photocatalysis illustrated a good dye removal efficacy by developed CDs with an average of 90.73, 98.25, 52 and 6.13% degradation in Methylene blue (MB), Malachite green (MG), Rhodamine 6G (Rh 6G) and Methyl orange (MO) upon 70 min of irradiation with mercury lamp. Additionally, the proton NMR, FTIR and FESEM results of the recycled samples also confirm the complete degradation of MG dye with the application of N-CDs.