Development and optimization of polyoxometalate-modified metal-organic frameworks for efficient removal of sulfur and nitrogen compounds from diesel fuel under visible light

As global fuel standards tighten, stripping sulfur and nitrogen compounds from diesel has emerged as a pivotal hurdle for both environmental protection and industrial innovation. This study explores an innovative route to synthesize metal-organic frameworks (MOFs) infused with Keggin-type polyoxometalates (Mo₆W₆), crafting next-generation nanocomposites tailored for catalytic oxidative desulfurization (ODS) and denitrogenation (ODN). Zirconium- and copper-based MOFs (NUiO-66 and HKUST) were effectively functionalized with Mo₆W₆, a modification verified through FTIR and XRD characterization. Their catalytic performance in eliminating dibenzothiophene (DBT) and quinoline (Qu) from model diesel was assessed under gentle reaction conditions, employing tert-butyl hydroperoxide (TBHP) as the oxidant and harnessing visible LED light for activation. Results obtained from the present study indicated that embedding polyoxometalates within MOFs markedly boosted catalytic efficiency for the concurrent removal of sulfur and nitrogen species. These nanocomposites offer a cost-efficient, high-performance pathway to cleaner diesel production, eliminating the need for the severe conditions typical of hydrodesulfurization. This study highlights the promise of polyoxometalate-engineered MOFs as sustainable, scalable catalysts, paving the way for cleaner fuel production in modern petroleum refining.