Syntheses and ultra-deep desulfurization performance of sandwich-type polyoxometalate-based TiO₂ nanofibres

The sandwich-type polyoxometalate-based TiO₂ nanofibres were prepared successfully by electrospinning combining with chemical reaction and employed in ultra-deep desulfurization. OTA–CoVW–TiO₂ nanofibres (OTA = CH₃(CH₂)₁₇(CH₃)₃N, CoVW = [Co₄(H₂O)₂(VW₉O₃₄)₂]¹⁰⁻) confirmed the excellent desulfurization performance in extraction catalytic oxidative desulfurization system (ECODS). At 323 K, the 500 ppm DBT (dibenzothiophene) model oil was entirely removed within 20 min using 0.010 g 45 wt% OTA–CoVW–TiO₂ nanofibres as catalyst when O/S molar ratio was 4:1 and the dosage of model oil was 5 mL. The catalysts could be recycled and reused at least five times without remarkable decrease in catalytic activity. The desulfurization efficiencies for different substrates were shown as following order: DBT > 4,6-DMDBT (4,6-dimethyl-dibenzothiophene) > BT (benzothiophene). Moreover, the possible mechanism was also elucidated.