Crosslinked chitosan embedded TiO2 NPs and carbon dots-based nanocomposite: An excellent photocatalyst under sunlight irradiation.

Abstract Herein, a new hybrid nanocomposite, comprising of titania nanoparticles (TiO2 NPs) and carbon dots (CDs) deposited polyvinyl imidazole crosslinked chitosan [cl-Ch-p(VI)/TiO2NPs-CDs] has been developed. The nanocomposite has been synthesised by in-situ deposition of TiO2 NPs and CDs onto the surface of the copolymer under microwave irradiation. To the best of our knowledge, this is the first time that this in-situ approach has effectively been applied to fabricate green fluorescent CDs from sugar cane juice at moderate temperature (75 °C) under microwave irradiation. The developed nanocomposite has been characterized using UV–Vis spectroscopy, 13C NMR, XRD, HR-TEM, STEM and XPS analyses. The results suggest the successful deposition of TiO2 NPs and CDs onto the surface of crosslinked chitosan. The experimental studies indicate that the NPs/CDs-impregnated nanocomposite allows efficient photocatalytic degradation of toxic organic compounds (~98.6% degradation of 2,4-dicholorophenol, ~95.8% degradation of Reactive Blue 4, ~98.2% degradation of Reactive Red 15) in the presence of sunlight. Finally, LC-MS analysis of the resultant degraded materials reveals the formation of organic molecules with lower molecular mass.