Keggin- and Dawson-type polyoxotungstates immobilized on poly(3,4-ethylenedioxythiophene)-coated zerovalent iron nanoparticles: Synthesis, characterization and their catalytic oxidative desulfurization activity

Abstract

This work reports synthesis of new and hybrid nanocomposites composed of Keggin- and Dawson-type polyoxotungstates (POTs), namely Na3[PW12O40] (PW12) and K6[P2W18O62] (P2W18), immobilized on poly(3,4-ethylenedioxythiophene) (PEDOT) coated zerovalent iron (Fe0). The synthesized catalyst samples were analyzed by different characterization techniques including powder XRD, VSM, FESEM, EDX and DRS. The Fe0@PEDOT\\POTs magnetic nanocomposites have been investigated as efficient heterogeneous nanocatalysts for catalytic oxidative desulfurization (ODS) of model and real gasoil fuels. The catalytic ODS was carried out at various experimental conditions to assess the influences of individual reaction variables, such as nanocatalyst dosage, sulfur content (in model fuel), reaction time and reaction temperature. At the same experimental conditions, Keggin POTs-based catalyst (Fe0@PEDOT\\PW12) exhibited higher desulfurization activities (98.6% and 93.2% for model fuel and real gasoil, respectively) than Dawson- POTs-based (Fe0@PEDOT\\P2W18) catalyst (93.1% and 84% for model fuel and real gasoil, respectively). According to the results, the Fe0@PEDOT\\PW12 reusable nanocatalyst can retain high desulfurization efficiency after six reaction cycles.