A novel ZnO/FeOCl composite as a photo-Fenton catalyst for degradation tetracycline under visible light

A series of novel ZnO/FeOCl photo-Fenton catalysts were prepared using a simple calcination method. These composite catalysts were evaluated for tetracycline (TC) degradation under simulated sunlight. The photo-Fenton tests revealed that the ZnO/FeOCl composite catalysts exhibited higher activity than pure FeOCl due to the presence of ZnO. Specifically, the degradation of TC by 20% ZnO/FeOCl reached 93.9% in 60 min, which was attributed to the formation of an n–n heterojunction between ZnO and FeOCl that enhanced the separation efficiency of photogenerated electron–hole pairs. Additionally, the TC removal efficiency remained at 84.4% after four cycles, indicating good structural stability of the composite catalyst. A proposed mechanism for TC degradation by ZnO/FeOCl catalysts, based on free radical trapping experiments, suggested that hydroxyl radicals (·OH) were the primary active species. This study provides new insights into the synthesis of photo-Fenton catalysts and the efficient treatment of antibiotic-contaminated wastewater.