CoFe2O4/resorcinol–formaldehyde resin p–n heterojunctions with a built-in electric field for photo-self-Fenton degradation of tetracycline hydrochloride

Abstract

The efficient removal of tetracycline hydrochloride (TC-HCl), a widely used antibiotic and prevalent water pollutant, remains a pressing challenge in wastewater treatment. Photo-Fenton systems with in situ H₂O₂ generation represent a promising solution, but their performance is often hampered by sluggish charge separation. Constructing p–n heterojunctions with a built-in electric field (IEF) offers a powerful strategy to overcome this limitation. Herein, we report MOF-derived CoFe₂O₄/resorcinol–formaldehyde resin (RF) heterostructures as an efficient photo-self-Fenton catalyst for TC-HCl degradation. The optimized CoFe₂O₄/RF achieved 89.2% TC-HCl removal within 60 min, with degradation rates 7.7 and 15.6 times higher than those of pure CoFe₂O₄ and RF, respectively. Comprehensive analysis revealed that the IEF in CoFe₂O₄/RF effectively facilitates charge separation, enhancing catalytic efficiency. Liquid chromatograph-mass spectrometry (LC-MS) and QSAR-based toxicity assessment confirmed stepwise degradation of TC-HCl into less toxic intermediates. This work demonstrates the potential of p–n heterojunctions with an IEF as robust, efficient, and environmentally photo-Fenton catalysts for water purification.