Synthesis And Deep Desulfurization Properties Of Polyoxometalates-Based TiO₂ Nanofibres Materials

This thesis focus on the design and synthese based on polyoxometalates?POMs?TiO₂ nanofibres materials.Their structures and patterns have been characterized by IR analysis,XRD analysis and SEM method.These compounds were researched on the desulfurization properties,reusability and catalytic mechanism.The experiment results as follows:1.Firstly,sandwich type polyoxometalate Na₁₀[Co₄?H₂O?₂(VW₉O₃₄)₂]·35H₂O was synthesized,?OTA?₁₀[Co₄?H₂O?₂(VW₉O₃₄)₂]·35H₂O?abbreviated OTA-CoVW?was prepared via ionic exchange of Na₁₀[Co₄?H₂O?₂(VW₉O₃₄)₂]·35H₂O and octadecyl trimethyl ammonium chloride OTA·Cl.We prepared TiO₂ nanofibres by electrospinning,and then OTA-CoVW was loaded on TiO₂ nanofibres,a series of x wt.%?OTA?₁₀[Co₄?H₂O?₂(VW₉O₃₄)₂]-TiO₂ nanofibres?abbreviated OTA-CoVW-TiO₂NF?were obtained,the catalysts,ionic liquid 1-Butyl-3-methylimidazolium hexafluorophosphate?[Bmim]PF₆?and H₂O₂ were constituted the extraction catalytic oxidation desulfurization system?ECODS?.At 323 K,500 ppm DBT model oil could be transformed into DBTO₂ within 20 min with 0.01 g 45-OTA-CoVW-TiO₂ NF.The desulfurization efficiencies for different substrates followed the order of DBT>4,6-DMDBT>BT.In addition,the catalysts could be recycled and reused at least five times without remarkable decrease in catalytic activity.2.A series of amphipathic TiO₂ nanofibres catalysts based on lindqvist polyoxometalates were prepared successfully by electrospinning combining with chemical reaction,which were employed in ultra-deep desulfurization investigation on BT,DBT and 4,6-DMDBT.At 333 K,the 100%desulfurization efficiency of 500ppm DBT model oil was obtained using 0.01 g 50-DTA-MoO-TiO₂ NF within 40 min,and the n?H₂O₂?/n?DBT?molar ratio is 2.The catalysts could be easily regenerated and reused for six consecutive cycles with unnoticeable decrease in catalytic activity.Moreover,the possible mechanism was also elucidated.