Carbon Quantum Dots Decorated Bismuth Oxychloride Nanocomposites with Enhanced Photocatalytic Activity Towards Pollutants Degradation and Mechanism Study

Utilization of visible light and the separation of electron–hole pairs is the forever theme of photocatalysis. In this work, a series of carbon quantum dots decorated bismuth oxychloride (CQDs/BiOCl) were prepared by solvothermal method, and served as photocatalysts for Rhodamine B (RhB) degradation under visible light. CQDs/BiOCl-8 (8 mL CQDs) can remove 97% RhB (20 mg/L) within 40 min, which is 11.3 times higher than pure BiOCl. This can be attributed to the fact that the excitation-independent up-conversion fluorescent characteristics of CQDs enable BiOCl to be excited by visible light. Furthermore, CQDs acted as electron libraries, which enhanced the separation of photoinduced electron–hole pairs in BiOCl. Quenching experiments confirmed that the superoxide (·O 2 − ) and hole (h + ) were main reactive oxygen species (ROS) for RhB degradation. This study provides a strategy to design highly efficient photocatalysts for environmental remediation. Graphical Abstract