Straightforward approach to promote an efficient reutilization of POM@MOF catalysts in oxidative desulfurization processes

A straightforward innovative strategy to improve the reusability of a polyoxometalate / porous metal-organic framework (POM / MOF) heterogeneous catalysts based in suitable structural modification by thermal treatment is reported in this manuscript for the first time. The incorporation of the active Keggin-type phosphomolybdate anion ([PMo 12 O 40 ] 3- , PMo 12 ) into the porous Zeolitic Imidazolate Framework (ZIF-8) led to the formation of the composite material PMo 12 @ZIF-8. This material exhibited catalytic activity during the first use but could not be reused in subsequent oxidative desulfurization (ODS) cycles of a multicomponent model diesel (2000 ppm S). Remarkably, an appropriate post-synthetic thermal treatment at temperatures slightly below the structural collapse point (400 °C and 500 °C), as well as at 550 °C, enabled efficient reutilization of the material. This modified material was reutilized for at least five consecutive ODS cycles without any observable loss in catalytic performance. These results confirm the integrity and durability of the heterogeneous catalyst. The methodology here developed is a reference that can be adapted to improve the robustness of active POM@MOF based catalyst, increasing the viability of these highly active materials for industrial application. • Porous PM O12 @ZIF-8 composite materials were prepared by a straightforward synthetic procedure • Appropriate post-synthetic thermal treatment induced effective structural modifications • Thermally modified materials at 400 and 500°C revealed efficient and sustainable catalysts for oxidative desulfurization reaction • Promising modification strategy to develop much more sustainable POM@MOF-based catalysts