| Heterpolyoxometalates ?HPAs? have arosed the universal attention which not only due to their richness architecture and chemical composition, but also the potential applications, such as medicine, material science, electrochemistry, magnetism, and catalysis in particular. The synthesis of new inorganic-organic hybrid materials based on POMs with excellent catalytic properties and high stability in water has gradually been in a hot research in this field. The Dawson-type{S2Mo18O62} can undergo stepwise reversible multielectro-transfer process, so we synthesized six new inorganic-organic hybrid materials based on molybdosulfates and ionic liquid via conventional method and electrolytic method in this paper:(C16H18N3S)2[NBu4]2[S2Mo18O62]·2CH3CN ?1? (C10H16N)4[S2Mo18O62]·CH3CN ?2? (C7H13N2)10 [S2Mo17?Mo1?O62]2·3CH3CN ?3? (C8H15N2)5[S2Mo17?Mo1?O62] ?4? (C10H19N2)5[S2Mo17?Mo1?O62] ?5? H[N?C2H5?4]4[S2Mo17?Mo1?O62]·CH3CN ?6?All the above compounds except the fifth compound were characterized by IR, elemental analysis, and single crystal X-ray diffraction to identify their structures. These compounds were used to fabricate six chemically modified carbon paste electrode ?CPE? by direct mixing, respectively. The electrochemical behavior and electrocatalysis of six CPEs have been studied in 1 mol/L H2SO4 aqueous solution. All of these CPEs exhibit five pairs of redox peaks in the potential range -300 mV to 700 mV and have more positive first redox potentials than P2Mo18O626-. These CPEs showed high electrocatalytic activity toward the reduction of nitrite, bromate and hydrogen peroxide and remarkable stability after 500 circles.We explored their catalytic oxidative behavior. We choiced compound 3 as the catalyst for the deep desulfurization of DBT in model oil, using hydrogen peroxide as the oxidant under mild conditions. The catalytic activity of compound 3 is evaluated by the orthogonal test to determine the optimized conditions. The optimized conditions are as follows:1.5 mmol catalyst,5 mL acetonitrile as solvent, n?H2O2?/n?model oil?=6:1, and 60 ? for 60 min, the sulfur removal efficiency of 100%. After eight cycles, the catalytic activity still remained high level. At the same time, we choiced compound 5 as catalyst to selective oxidation of benzyl alcohol into benzaldehyde, and the catalyst exhibits 75.0% conversion.We researched the degradation of methylene blue ?MB? optical activity of compound 4 in the UV-ligth area. The results indicated that the catalyst exhibits the perfect photocatalytic activity and 94% MB was degraded after irradiation for 30 min. |
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