Investigating the role of ultrasound in improving the photocatalytic ability of CQD decorated boron-doped g-C3N4 for tetracycline degradation and first-principles study of nitrogen-vacancy formation

Abstract

Graphitic carbon nitride (CN) is recognized as a promising photocatalyst for energy and environmental remediation. However, challenges persist due to limited CN surface-active sites and poor electronic properties. To overcome such challenges, we have synthesized Carbon Quantum Dots decorated Boron-doped Exfoliated CN (CQD@B-ECN) via ultrasound-assisted thermal polycondensation method. The substitutional boron doping favored nitrogen-vacancy as evident from experimental results and DFT calculations, which accelerated the charge separation/transfer and the CQD incorporation broadens the light-harvesting ability through photon upconversion. Moreover, the specific surface area of 2CQD-2B-ECN (685 m2/g) was significantly greater than CN providing enormous active sites. 2CQD-2B-ECN were evaluated using Tetracycline (TC) antibiotic, where photocatalysis and sonocatalysis showed 68% and 0.2% degradation in 120 min, respectively. Remarkably, sonophotocatalysis exhibited 84% TC degradation with a synergy index of 1.2 and complete degradation within 180 min. This work reveals an insight into CQD-B-ECN as a novel sonophotocatalyst for the degradation of diverse recalcitrant pollutants.