Enhancing Tetracycline Degradation with Biomass Carbon Quantum Dot (CQDs)-Modified Magnetic Heterojunction CeO2-Fe3O4 under Visible Light

This research investigates the synergistic enhancement of semiconductor catalysts through the incorporation of carbon quantum dots (CQDs) within CeO2-Fe3O4 Type-II heterojunction photocatalysts. Subsequent to the successful synthesis of these modified photocatalysts, a thorough assessment of their catalytic performance is conducted. Notably, the introduction of CQDs results in a 21% increase in pollutant degradation capacity compared to unmodified heterojunctions, with a remarkable removal efficiency of 96% for the target pollutant TC. Comprehensive analyses employing electrochemical impedance spectroscopy (EIS), UV-vis spectroscopy, and photocatalytic experiments provide substantial evidence for the efficacy of CQDs in enhancing light absorption properties within the CeO2-Fe3O4 heterojunction. This enhancement is attributed to a notable suppression of electron-hole pair recombination, facilitating the generation of reactive oxygen species (ROS) such as ·O2- and ·OH. This, in turn, the promotion of Ce4+/Ce3+ and Fe3+/Fe2+ cycles takes place, collectively enhancing the responsiveness of the photocatalyst to visible light. The photocatalysts demonstrate enduring catalytic and magnetic stability over five cycles, as indicated by the sustained high-performance retention. Detailed analysis using TOF-LC-MS has revealed two highly efficient degradation pathways for the for the target pollutant. The findings contribute valuable insights for advancing the performance of heterojunction photocatalysts.