Abstract:

Sulfur emission from fossil fuel combustion can lead to acid rain; thus, it is essential to reduce the sulfur content of fuel through deep desulfurization. The polyoxometalate (POM)-based covalent organic framework (COF) is considered an excellent catalytic material because it exhibits excellent redox activity, adjustable hydrophilicity, and good recyclability. The successful encapsulation of vanadium-containing POM ((NH₄)₅H₆PMo₄V₈O₄₀, PMo₄V₈) into EB-COF (EB represents ethidium bromide) is achieved via ion exchange, and a new composite of PMo₄V₈@EB-COF is produced. The composite structure is determined through X-ray diffraction analysis, infrared spectroscopy, and elemental analysis. The oxidative desulfurization potential of PMo₄V₈@EB-COF is studied using dibenzothiophene as a model fuel and oxygen as an oxidizer. The catalytic results show that PMo₄V₈@EB-COF exhibits an excellent desulfurization performance. At 100 ℃, dibenzothiophene (DBT) conversion reaches 96.6% after the reaction for 2.5 h. In this experiment, chemistry knowledge of various subjects as well as concepts of synthesis chemistry and green chemistry are involved. Moreover, this experiment is suitable for modular teaching with individual sections to meet experimental teaching needs. Through this experiment, students can cultivate the spirit of innovation and improve comprehension abilities.

Key words: Polyoxometalates, Covalent organic frameworks, Oxidative desulfurization, Innovation experiment