Microwave-assisted synthesis of carbon quantum dots and their integration with TiO2 nanotubes for enhanced photocatalytic degradation

This study demonstrates the successful synthesis of carbon quantum dots (CQDs) using the microwave method. Additionally, the hydrothermal method is employed to synthesize CQDs-decorated TiO 2 nanotubes (CQDs@TNT) from CQDs decorated TiO 2 (CQDs@TiO 2 ). The CQDs induce the quantum confinement effect, observed by employing fluorescence spectroscopy (FL). The decoration of CQDs also results in a 2.92 eV reduction in the band gap in CQDs@TNT. X-ray photoelectron spectroscopy (XPS) reveals the elemental composition of both CQDs and TiO 2 , including Ti - O, C - O, Ti -O -C, C - C, and C - - O bonds. XRD spectroscopy confirms a reduction in crystallite size and negative microstrain due to compressive strength. The degradation study demonstrates the remarkable photocatalytic activity and stability of CQDs@TNT in the presence of tetracycline (TC) as the target pollutant under simulated visible light. The time dependence of the photodegradation of TC is also studied, and the system is found to be following pseudo second -order kinetics.