Vanadium-substituted heteropolyacids (H3+mPW12−mVmO40) encapsulated in Fe3O4@UiO-66 magnetic core–shell microspheres as excellent catalysts for oxidative desulfurization under oxygen

Abstract

In this study, the novel magnetic core–shell composites Fe₃O₄@UiO-66-HPA, consisting of magnetic Fe₃O₄@UiO-66 and vanadium-substituted Keggin-type heteropolyacid active species supported by Zr-MOF, were successfully prepared via a one-pot method and fully investigated using FT-IR, XRD, SEM, TEM, TEM-EDX, ICP, VSM and N₂ adsorption–desorption isotherms. The synthetic composites were employed as catalysts in an ODS system of simulated fuel under oxygen. The catalyst Fe₃O₄@UiO-66-PW₉V₃ exhibits the supreme catalytic performance in this work, with sulfur removal of 99.85% and a TOF value of 31.16 h⁻¹ under optimal reaction conditions (0.2 g catalyst mass, 60 °C reaction temperature, 500 rpm stirring speed, 1 L min⁻¹ oxidant quantity and 180 min reaction time), and can also be recycled ten times without apparent loss of catalytic performance. Furthermore, the kinetic study shows that the ODS process accords with the pseudo-first-order model.