Efficient Catalytic Ozone Degradation of Organic Pollutants by Anchoring MnFe2O4 on Chitosan-Derived N-Doped Carbon-Modified MoS2

Organic pollutants present in wastewater pose severe threats to aquatic organisms and human health. In this study, a magnetic MFO/NCS@MoS2 composite catalyst was successfully synthesized via a hydrothermal method and applied for catalytic ozonation of methylene blue (MB). The catalyst was systematically characterized using multiple techniques including XRD, FT-IR, SEM, TEM, and XPS. Results revealed that the incorporation of chitosan (CS) effectively expanded the interlayer spacing of MoS2, which not only enhanced the structural stability but also promoted mass transfer and full exposure of active sites, thus promoting the generation of free radicals and nonfree radicals. As an electron donor, Mo4+ and unsaturated sulfur atoms on the surface of MoS2 not only provided active centers for catalytic ozonation, but also promoted the valence cycling between Mn2+/Mn3+ and Fe2+/Fe3+. In this way, the active centers of Mo4+ and unsaturated sulfur from MoS2 cooperated with the Mn/Fe bimetallic centers from MnFe2O4 to make the catalytic reaction continue. The 1.0MFO/NCS@MoS2/O3 system exhibited excellent catalytic activity and removed 99.13% of MB within 6 min. In addition, it possessed remarkable structural stability, strong anti-interference capability, and environmental compatibility. Radical trapping experiments verified that 1O2, O2•–, and •OH were involved in the degradation process. This study provides a new design strategy for developing efficient and recyclable ozonation catalysts.