Polyoxometalate-based ionic liquid supported on graphite carbon induced solvent-free ultra-deep oxidative desulfurization of model fuels

•POM-IL supported on graphite carbon was prepared and applied in ODS.•[PSPy]PMo/GC was employed to build heterogeneous desulfurization system.•The removal of DBT reached 100% in the solvent-free ODS system under mild conditions.•Kinetics studies were taken to better understanding the oxidation reactions.•Supported catalyst could be separated and recycled easily in the solvent-free system.

A supported heterogeneous catalyst with polyoxometalate-based ionic liquid (POM-IL) [N-(3-sulfonatepropyl)-pyridinium]3PMo12O40 ([PSPy]PMo) served as active component was prepared and graphite carbon (GC) with layer structure was used as support. Characterizations of the supported catalyst by FT-IR, Raman, XRD, XPS and TEM confirmed that IL was immobilized on GC successfully and the structure was retained after the hydrothermal impregnation method. The as-prepared catalyst exhibited high catalytic performance in the solvent-free oxidative desulfurization system. Various of reaction conditions were investigated and the removal of dibenzothiophene reached 100% under the optimum conditions. Wettability experiments and kinetics studies were taken to better understand the oxidation reactions. In addition, the suggested mechanism was given with the help of Gas Chromatography-Mass Spectrometer analysis. Moreover, the supported catalyst had a good recyclability, which made it have a promising prospect for industrial application.