Carbon Dots-Mediated Z-Scheme Heterojunction of UiO-66-NH(2)/BiOCl for Enhanced Visible-Light-Driven Degradation of Antibiotics and Dyes.

The ubiquitous accumulation of antibiotics and synthetic dyes in aquatic environments has emerged as a critical threat to the ecological integrity and human health. Visible-light-driven photocatalysis represents a sustainable strategy for decontaminating such pollutants; yet, its practical efficacy is often hampered by narrow light-harvesting ranges and rapid photogenerated carrier recombination. Herein, a ternary photocatalyst, namely, CDs/UiO-66-NH/BiOCl (CUCl), was rationally constructed by integrating carbon dots (CDs) into a UiO-66-NH/BiOCl Z-scheme heterojunction. Serving as an efficient electron reservoir, the introduced CDs not only significantly extended the visible-light absorption range but also effectively suppressed carrier recombination. Under visible-light irradiation, the optimized CUCl catalyst achieved remarkable degradation efficiencies of 87.2% and 98.8% for tetracycline and rhodamine B, respectively, outperforming the binary UiO-66-NH/BiOCl heterojunction and pristine BiOCl. Radical trapping experiments and photocatalytic mechanism investigations revealed that photogenerated holes (h) and superoxide radicals (·O) were the dominant active species responsible for pollutant degradation. Moreover, the CUCl catalyst exhibited excellent structural stability and reusability, retaining more than 85% of its initial catalytic activity after four consecutive reuse cycles. This work provides a novel and viable strategy for fabricating high-efficiency, stable environmental photocatalysts via the synergistic integration of Z-scheme heterojunctions and carbon dot functionalization.