Photo-responsive catalyst activated Peroxymonosulfate: Dynamic radical-nonradical pathway switching for tetracycline degradation in diverse environments

The efficient removal of organic pollutants from wastewater with diverse compositions remains a significant challenge due to the inherent limitations of traditional advanced oxidation processes (AOPs). Radical-dominated pathways are often inhibited by water matrix components, whereas nonradical pathways, although more selective and tolerant, exhibit slower reaction rates. Herein, we developed a photo-responsive Fe–B@C catalyst that enables dynamic regulation of reactive oxygen species (ROS) pathways through light irradiation, effectively acting as a switch between nonradical and radical-nonradical synergistic mechanisms. Under dark conditions, the system predominantly generates singlet oxygen ( 1 O 2 ), maintaining high stability against inorganic salts, humic acids, and broad pH variations. Upon illumination, the catalyst switches to a synergistic pathway involving 1 O 2 , hydroxyl radicals (•OH), and sulfate radicals (SO 4 − •), achieving near-complete tetracycline removal and enhanced mineralization. Mechanistic studies reveal that boron facilitates the Fe 3+ /Fe 2+ redox cycle and promotes ROS generation, while light precisely controls the activation mode. This work demonstrates a smart catalyst design strategy, allowing AOPs to adapt to varying wastewater compositions, offering a promising solution for tailored and high-efficiency water treatment.