Decavanadates anchored into micropores of graphene-like boron nitride: Efficient heterogeneous catalysts for aerobic oxidative desulfurization

Abstract

Catalytic aerobic oxidation of aromatic sulfides to their corresponding sulfones could provide a novel route for producing fuels with ultra-low sulfur content, solving the increasingly severe air pollution problems. In this work, a series of heterogeneous catalysts were synthesized by anchoring decavanadate ionic liquids (ILs) into the micropores of graphene-like hexagonal boron nitride (g-BN). The as-prepared catalysts could inherit both the catalytic ability of polyoxometalate ILs (POM-ILs) and the separation efficiency of g-BN. Besides, the usage amount of POM-ILs could be reduced sharply. Under the optimized reaction conditions, sulfur removal of dibenzothiophene (DBT), as one of the most stubborn residuals in oil refining process, could rise up to 99.8% (≤1 ppm) in this proposed adsorptive and aerobic oxidative desulfurization (AAODS) process. In addition, excellent sulfur removal with oils of different sulfide concentrations, substrates and aromatics/olefins addition could also be achieved. Moreover, renewable recycling performance with 99.4% sulfur removal was observed after 6 times recycle. Finally, a possible reaction process was proposed depending on the experiment evidence from different aspects.