Tuning visible light-driven photocatalytic NO removal: Insights from glucose-derived CQDs/ZnO nanorods composite

Abstract

The potential of visible light photocatalysis in mitigating environmental pollutants has gained significant attention. In this study, we investigate the photocatalytic NO removal efficiency of oxygen defect-rich zinc oxide nanorods (ZnO NRs), facilitated by the incorporation of carbon quantum dots (CQDs) under mild conditions. The successful integration of CQDs with ZnO NRs represents a novel and sustainable approach for efficient NO removal under visible light irradiation. Notably, the CQDs/ZnO NRs shows a substantial increase in NO removal efficiency (71.9%), low toxicity (2.7%) and durability (only 7.7% efficiency reduction after five cycles). The synergetic effects of CQDs and oxygen defects within the ZnO NRs structure, which broadens the light absorption spectrum, facilitates electron separation, thus enhanced photocatalytic NO removal. Furthermore, photoluminescence, active species trapping experiments, and electron spin resonance analysis have confirmed the generation of hydroxyl radicals (•OH) and superoxide radicals (•O2–) during the excitation of electrons. Finally, the synergetic mechanism of CQDs and oxygen defects in ZnO NRs for amplifying visible-light-driven photocatalytic NO removal was elucidated.