Exceptional functionalized ionic liquid@metal–organic framework: A high-efficiency desulfurization platform for organic sulfide oxidation by reactive oxygen species

Abstract

There is a challenge with designing catalysts that simultaneously possess active sites for catalyzing the generation of reactive oxygen species (ROSs) and effectively overcoming mass transfer resistance in oil–water biphasic systems. In this study, a novel, highly efficient oxidative desulfurization (ODS) strategy is proposed that uses an ILs-loaded metal–organic framework (MOF) coupled material as a catalyst. The IL@MOF ([Hnmp]HSO4@MIL-125(Ti)) coupled material prepared by loading [Hnmp]HSO4 onto MIL-125(Ti) has catalytic-adsorption synergistic capability. It demonstrated outstanding oxidative desulfurization performance by achieving nearly a 100 % removal of dibenzothiophene (DBT) from model oil with a dosage of 0.04 g IL@MOF per 10 mL of model fuel under mild conditions (50 °C, 10 min). By comparing the experimental results with the characterization data, it is suggested that [Hnmp]HSO4@MIL-125(Ti) converts superoxide radicals (•O2−) into 1O2 through oxygen vacancies (Ov) and that the catalytic action of Ti on the oxidation of DBT is primarily based on a 1O2-driven non-free radical mechanism. [Hnmp]HSO4@MIL-125(Ti) serves as a favorable medium for contact to be made between ROSs and sulfides, which indicates an efficient catalytic-adsorption synergy.