Magnetic FeP/Fe3O4 multi-shell heterostructures for enhanced peroxymonosulfate activation in accelerating tetracycline degradation

Iron-based heterogeneous catalysts have been demonstrated considerable potential in peroxymonosulfate (PMS) activation for the degradation of organic pollutants degradation, yet their catalytic efficiency remains constrained by insufficient active sites and limited electron transfer capability. This study presents a rationally designed magnetic FeP/Fe 3 O 4 multi-shell heterostructure which provides abundant active sites, and enhanced electron transfer capability. The FeP/Fe 3 O 4 /PMS system achieved complete tetracycline (TC) removal within 20 minutes, exhibiting a pseudo-first-order kinetic constant 5.7-fold greater than that of Fe 2 O 3 /PMS system. Electrochemical analysis indicates that the FeP/Fe 3 O 4 heterostructure substantially enhances current density and catalytic activity compared to the Fe 2 O 3 /PMS system, primarily through optimized electron transport. Furthermore, its stronger spontaneous PMS adsorption capacity synergistically facilitates the continuous generation of reactive oxygen species, ultimately achieving efficient pollutant degradation. Results indicate that TC was removed via mixed radical and nonradical pathways, and the degradation intermediates and possible degradation pathways were elucidated. In addition, the FeP/Fe 3 O 4 /PMS system maintained high efficiency and stability across a wide pH range and in complex water conditions, and exhibited broad applicability for the degradation of various organic pollutants. This study provides valuable insights into the design of high-performance iron-based catalysts, and advances the fundamental understanding of the PMS activation mechanisms. • Efficient antibiotic degradation via rapid PMS activation. • Magnetic recovery capability enables near-lossless reuse cycles. • Defect-rich heterointerfaces boost electron transfer kinetics. • Robust catalytic performance persists in diverse aqueous systems.