S-doped core–shell heterojunction Fenton catalyst (Fe3O4-S@PVP@UIO-66-(SH)2) for enhanced activation of hydroxyl radicals: Synergistic enrichment and degradation mechanism

Abstract

The design of catalysts for the rapid activation of H2O2 and synergistic enrichment of pollutants is an effective strategy to improve catalytic performance. Herein, an Fe3O4-S@PVP@UIO-66-(SH)2 (FPUSH) heterojunction was successfully synthesized to form a core–shell-doped multiphase Fenton catalyst with both internal doping and outer encapsulation structures, which had excellent mass and efficient electron transfer performance. Levofloxacin can be adsorbed (Qmax was 141.44 mg g−1) and degraded at a removal efficiency of 97.70% within 120 min. The recycled efficiency of FPUSH was maintained at more than 90% after five recycles. The experimental and DFT results showed that the introduction of S improved the electron density of Fe atomic orbitals, promoted the electron transfer of Fe(II)/Fe(III), and enhanced the catalytic performance of Fe active sites. The degradation pathway of LVFX and the toxicity of intermediate products were predicted. This work provides new ideas and insights for the application of nonmetals in high-performance multiphase Fenton systems.