Facile synthesis of magnetic resorcinol–formaldehyde resin Fe₃O₄@RF-Au composites for enhanced tetracycline photodegradation with simultaneous H₂O₂ production

Magnetic Fe₃O₄ resorcinol–formaldehyde (RF) resin core–shell composites loaded with Au nanoparticles (Fe₃O₄@RF-Au) were prepared via a hydrothermal photoreduction strategy for efficient production of H₂O₂ and degradation of tetracycline (TC). Under visible light illumination, Fe₃O₄@RF-Au reduced oxygen to produce H₂O₂ through a two-electron reduction pathway. Fe(II) simultaneously catalysed the decomposition of H₂O₂ to generate⋅OH for the degradation of TC. The Fe₃O₄@RF-Au₂ photocatalyst demonstrated the highest photodegradation efficiency of 96.8% against TC and a high H₂O₂ yield of ~326 µmol L⁻¹ in an open atmosphere, which was enhanced 6.5 times that of Fe₃O₄@RF. The introduction of RF coating and plasmonic Au nanoparticles significantly enhanced the light-harvesting efficiency, O₂ adsorption capacity, photogenerated carrier migration, and separation, thereby boosting the photocatalytic performance. This study provides a promising photocatalyst for in situ production of H₂O₂ and remediation of antibiotic-contaminated water.