Synergistic combination of the nanoporous system of MOF-808 with a polyoxomolybdate to design an effective catalyst: simultaneous oxidative desulfurization and denitrogenation processes

Abstract

The encapsulation of a polyoxomolybdate, H₃(PMo₁₂O₄₀)·nH₂O (PMo₁₂), in the nanoporous MOF-808 framework was carried out for the first time by a straightforward in situ method based on a “bottle-around-the ship” approach, to prepare an unprecedented nanocomposite, PMo₁₂@MOF-808. This material revealed notable catalytic activity for simultaneous oxidative desulfurization and denitrogenation of a model fuel containing the most representative refractory sulfur and nitrogen compounds in fuels: near complete desulfurization and denitrogenation were achieved after 1 h using the H₂O₂ oxidant. Moreover, PMo₁₂@MOF-808 showed high stability and the nonexistence of activity loss for consecutive recycling reactions. The absence of PMo₁₂ leaching and, simultaneously, the non-occurrence of cavity blockage reflects the ideal synergistic combination of the pore size to accommodate guest active PMo₁₂ with pore entrance dimensions that promote a high diffusion of sulfur/nitrogen compounds and H₂O₂ during concurrent oxidative desulfurization and denitrogenation reactions.