Engineering MOF-808 composites with peroxo-polyoxometalates: impregnation vs. solvothermal synthesis for optimal catalytic oxidative desulfurization

The synthesis pathway critically dictates the physicochemical properties and ultimate performance of heterogeneous catalysts. In this study, a peroxophosphotungstate (PW4) was encapsulated into zirconium-based metal – organic framework (MOF-808) via two distinct strategies: post–synthetic impregnation and one–pot solvothermal synthesis. Although both composites exhibited high initial activity in the extraction and oxidation desulfurization of model diesel, PW4@MOF-808-S demonstrated exceptional stability, with only a 5.1% efficiency loss after ten cycles. This superior performance is attributed to the more stable encapsulation achieved through the in-situ approach. Furthermore, PW4@MOF-808-S achieved 99.9% desulfurization under optimized mild conditions (70°C, O/S = 3). This work underscores that the choice of synthesis strategy is paramount for engineering optimal activity and long-term stability in POM@MOF composites.