With the increasingly strict limitations on emission standards of vehicles, deep desulfurization in fuel is indispensable for social development worldwide. In this study, a series of hybrid materials based on SiO₂-supported polyoxometalate ionic liquid were successfully prepared via a facile ball milling method and employed as catalysts in the aerobic oxidative desulfurization process. The composition and structure of prepared samples were studied by various techniques, including FT-IR, UV-vis DRS, wide-angle XRD, BET, XPS, and SEM images. The experimental results indicated that the synthesized polyoxometalate ionic liquids were successfully loaded on SiO₂ with a highly uniform dispersion. The prepared catalyst (C₁₆PMoV/10SiO₂) exhibited good desulfurization activity on different sulfur compounds. Moreover, the oxidation product and active species in the ODS process were respectively investigated via GC-MS and ESR analysis, indicating that the catalyst can activate oxygen to superoxide radicals during the reaction to convert DBT to its corresponding sulfone in the fuel.

Efficient removal of refractory sulfides using a facilely constructed MoO ₂ /BCN catalyst.

Porous polyanionic liquids (PIL) were constructed via a soft template method. Phosphomolybdic acid (PMA) anions were uniformly loaded into the pores by ion exchange. Various characterizations of the synthesized catalysts confirmed the successful synthesis of the designed catalysts. Deep oxidative desulfurization was achieved under mild reaction conditions.

The effective and deep removal of unreactive sulfides to achieve ultra-low-sulfur or sulfur-free oils has recently attracted extensive attention. In this work, a series of UiO-66 based catalysts have been prepared facilely for the effective removal of unreactive sulfides. Here, the incorporation of nitro functional groups into UiO-66, along with the construction of defects, results in remarkable sulfur removal for dibenzothiophene (DBT), achieving oil with sulfur content of less than 1 ppm. The successful construction of the designed catalysts was verified through a series of characterization studies. The exposed unsaturated metal sites help provide significantly more active reaction sites. In addition, the incorporated nitro group, with its electron-withdrawing property, would help increase the Lewis acidity of the catalytic metal sites. Thus, the catalytic oxidative capability of the designed UiO-66-based catalysts would be significantly increased. The enhanced catalytic oxidative performance helps ensure acceptable sulfur removal for oils with much higher sulfur concentrations. Additionally, the catalyst developed in this work can also be used to remove the derivatives of DBT with even lower reactivity. The relatively mild reaction conditions, combined with the exceptional sulfur removal, demonstrate the practicality of this reaction system.