杂多酸的共价负载及其对四氢噻吩氧化性能研究

首先采用改进的Hummers法制备氧化石墨烯（GO），用3-氨丙基三甲氧基硅氧烷（KH540）对GO进行表面改性，制得氨基改性氧化石墨烯NH₂-GO。然后，通过γ-(2,3-环氧丙基) 三甲氧基硅烷对单缺位的Dawson型磷钨酸盐K₁₀α-P₂W₁₇O₆₁]·20H₂O（P₂W₁₇）进行环氧基改性，制得环氧基改性的EPO-P₂W₁₇。最后，借助NH₂-GO与EPO-P₂W₁₇之间的席夫碱反应实现P₂W₁₇在GO上的共价固载，制得复合催化剂P₂W₁₇/GO。采用FT-IR、UV-Vis、TG、XPS、TEM等对复合材料的结构和组成进行了表征。以四氢噻吩（THT）作为催化评价的对象，初步考察了P₂W₁₇/GO的催化氧化活性。实验结果表明，共价负载在GO上的P₂W₁₇分散性良好，且复合催化剂P₂W₁₇/GO对THT表现出良好的催化活性和高的选择性。较小的P₂W₁₇/GO用量（0.02 g）下，以H₂O₂为氧化剂，反应75 min，THT转化率达100%；相对于EPO-P₂W₁₇，其催化活性提高了1.7倍；其催化H₂O₂氧化THT的过程符合准一级动力学模型。此外，该催化剂具有良好的重复使用性。

Covalently supported polyoxometalate and its catalytic oxidative desulfurization of tetrahydrothiophene

Firstly, the graphene oxide (GO) was prepared by the modified Hummers method, and modified with 3-aminopropyltrimethoxysilane to obtain NH₂-GO containing amino groups. Then, the single lacunary Dawson type tungstophosphate K₁₀α-P₂W₁₇O₆₁]·20H₂O (P₂W₁₇) was modified with γ-(2,3-epoxypropoxy) propyltrimethoxysilane (EPO) to prepare EPO-P₂W₁₇ containing epoxy groups. Finally, P₂W₁₇ was covalently bonded onto GO through the reaction of EPO-P₂W₁₇ with NH₂-GO to prepare P₂W₁₇/GO composite catalysts. The structure and composition of the composites were characterized by FT-IR, UV-Vis, TG, XPS, TEM, etc. Tetrahydrothiophene (THT) was used as the object of catalytic evaluation, and the catalytic oxidation activity of P₂W₁₇/GO was initially investigated. The results show that P₂W₁₇ covalent-supported on GO is well dispersed. And the oxidation process of THT catalyzed by P₂W₁₇/GO using H₂O₂ presented the high efficiency and selectivity. The conversion of THT could reach 100% at 75 min with H₂O₂ as oxidant under a small amount of P₂W₁₇/GO (0.02 g), and its catalytic activity is 1.7 times higher than that of EPO-P₂W₁₇. The catalytic oxidation of THT by P₂W₁₇/GO follows the quasi-first order kinetic model. More attractively, P₂W₁₇/GO could be well reused several times, stemming from the strong covalent bonding between P₂W₁₇ and GO surface.