In Situ Synthesis of Hierarchical POM@HUSY with Tunable Lewis and Bronsted Acid Sites for Deep Oxidative Desulfurization of Dibenzothiophene

Achieving excellent conversion and high stability is crucial in promoting practical applications of many emerging oxidative desulfurization (ODS) catalysts. Herein, POM@HUSYs were prepared through an in situ procedure, which enhanced the dispersion of polyoxometalate (POM) and reduced the leaching of active components. The catalyst was prepared in an acidic environment, which served a dual purpose. One purpose was to introduce Lewis acid sites in the zeolite, while the other was to synthesize the corresponding POM to provide Bronsted acid sites. By adjusting the synthesis conditions, catalysts with the best synergistic impact between the Lewis and Bronsted acid sites were discovered. The best sample HPW@HUSY24H-0.06M could achieve 99.2% DBT conversion in 120 min. Additionally, the obtained catalyst could efficiently adsorb the ODS products from the oil phase without extraction. The concept of a synergistic catalytic mechanism guides the future design and development of heterogeneous catalysts for ODS reactions.