Fuel oil consumption has consistently increased due to the increasing human population and energy demand worldwide. The high sulfur content in fuel oil is the leading cause of air pollution affecting our environment. Removal of sulfur species from liquid oil has become necessary to attain a safe and sustainable environment. In the present study, we report for the first time the facile fabrication of a series of POM@MOF nanocomposites made up of transition metals substituted Keggin-type PW11 and a zirconium-based MOF-808(Zr) by a one-pot encapsulation method. All the prepared nanocomposites were systematically characterized to validate their crystal structure and properties. The newly developed catalysts demonstrated the synergistic properties of POMs and MOFs and have been applied to test the catalytic oxidative desulfurization of organosulfur compounds present in n-dodecane. The experimental results showed that the Mn-substituted PW11@MOF-808 nanocomposite indicated the best catalytic activity with a DBT removal of 99.59 within a short time. The outstanding performance was due to the matching functionality and structural stability of the produced POM@MOF, giving rise to enhanced catalytic activity. Finally, the catalyst showed good activity and recyclability with no obvious loss in its initial activity after reusing ten consecutive cycles. © 2023 Elsevier B.V.