Magnetically Recoverable Polyoxometalate-Based Ionic Liquid Catalyst for Efficient Oxidative Desulfurization

A magnetic polyoxometalate-based ionic liquid catalyst, [OMIM] 3 PMo 12 O 40 /γ-Fe 2 O 3 @SiO 2 @ZIF-8, was synthesized via a hierarchical core–shell approach and applied in the oxidative desulfurization (ODS) of model oil. Characterization by XRD, FT-IR, SEM-EDS, XPS, and VSM confirmed the immobilization of active species and superparamagnetic properties, facilitating magnetic recovery. Under optimized conditions (50 mg catalyst, 0.5 mL ACN, 50 °C, H 2 O 2 /sulfur molar ratio = 8), 95.48% sulfur removal from dibenzothiophene (DBT, 500 ppm) was achieved within 180 min, with good activity toward 4,6-dimethyldibenzothiophene (4,6-DMDBT). Radical quenching experiments indicated that hydroxyl radicals (•OH) were the dominant reactive species. The catalyst maintained good activity over five cycles with only a slight decline in performance. This work provides an effective strategy for designing multifunctional polyoxometalate ionic liquid catalysts with improved mass transfer, catalytic efficiency, and recyclability for deep oxidative desulfurization. Graphical