Boosting Tetracycline Degradation with an S-Scheme Heterojunction of N-Doped Carbon Quantum Dots-Decorated TiO₂

Abstract

N-doped carbon quantum dots (N-CQDs) derived from the Rumex crispus L. plant were incorporated into TiO 2 via a facile hydrothermal method. Asprepared materials were characterized and used in the photocatalytic tetracycline (TC) degradation under UVA light irradiation by examining several operational parameters involving the N-CQDs amount, initial TC concentration, pH, and photocatalytic reaction time. XRD analysis revealed the conversion of the rutile phase to the anatase phase after the incorporation of N-CQDs into the TiO 2 structure. The results revealed that the N-CQDs/TiO 2 photocatalysts demonstrated the highest efficiency in TC degradation compared to other processes of adsorption, photolysis (UVA), and photocatalysis with TiO 2 (TiO 2 /UVA). Under optimized conditions, 10 mg/L TC at pH 5.15 with 0.2 g/L N-CQDs/TiO 2 catalyst showed 97.7% photocatalytic degradation for 120 min under UVA irradiation. The formation of an S-scheme heterojunction between N-CQDs and TiO 2 provided enhanced charge separation and strong redox capability, causing significant improvement in the photocatalytic performance of N-CQDs/TiO 2 . Trapping experiments showed that O 2•− and h + are the predominant reactive species for the TC elimination in an aqueous solution.

Economically viable N-doped graphene aerogel for the photodegradation of structurally different dyes and a plant-model-based environmental assessment

“…2c. 61 According to the observed Raman spectrum, N-GA has two distinct D and G bands characteristic of nano-carbons centered at ∼1355 and ∼1598 cm −1 , respectively (Fig. 2d).…”

Novel CQDs/BiOI Microspheres with Gradient Oxygen Vacancies for Efficient Photocatalytic Performance Boosting by the Synergism of Reactive Oxygen and Iodine Species

“…The diffraction peak is sharp, indicating the high purity preparation of BiOI. Moreover, the XRD patterns of CQDs/BiOI composites are like those of BiOI crystals, indicating that the crystal structure of BiOI is not changed after introducing CQDs [23–24] . There are no other peaks appears indicating that the high purity of CQDs/BiOI composites.…”

“…Moreover, the XRD patterns of CQDs/BiOI composites are like those of BiOI crystals, indicating that the crystal structure of BiOI is not changed after introducing CQDs. [23][24] There are no other peaks appears indicating that the high purity of CQDs/BiOI composites. The spectral characteristic diffraction peaks of CQDs/BiOI composites do not shift obviously, which indicates that the sedimented CQDs are not merged into the BiOI crystal.…”