离子液体作用下溶胶—凝胶法合成介孔材料的研究

发布时间：2018-06-16 18:02

本文选题：溶胶-凝胶 + 离子液体　；参考：《天津大学》2015年硕士论文

【摘要】：介孔材料因具有规则的周期性孔道结构、高度均一且相对较大的孔径(2-50 nm)、较大的孔体积、高的比表面积及孔结构可调等特性,使其在催化、吸附分离、生物医药合成等领域有着广泛的应用。离子液体因其具有界面张力低、良好的热稳定性、液态范围宽、双亲性、可形成广泛的氢键而具有良好的超分子结构等特性,近年来被广泛应用于材料合成领域。本文以二取代咪唑类离子液体为模板合成介孔氧化硅和介孔氧化铝材料,并最终得到了具有不同形貌和不同孔结构的介孔氧化硅和介孔氧化铝,在此基础上还对离子液体合成介孔材料的模板作用机理进行了深入研究。对于介孔氧化硅的合成,采用溶胶-凝胶法,以正硅酸乙酯(TEOS)为硅源、盐酸为催化剂,重点考察了模板剂用量和种类对合成的介孔氧化硅的孔结构及形貌的调控作用。研究结果表明:在介孔结构调控方面,分别以离子液体[Bmim]Tfo、[Bmim]Cl和[Bmim]PF_6单独为模板合成了具有蠕虫状介孔的氧化硅材料;分别以离子液体[Bmim]Tfo、[Bmim]Cl和[Bmim]PF_6和P123共模板合成了具有双介孔结构的高度有序介孔氧化硅;在形貌调控方面,以离子液体[Dmim]Cl为模板合成了空心球状氧化硅,以[Dmim]Cl与P123共模板合成了管状氧化硅,其管壁为高度有序介孔。对于介孔氧化铝的合成,采用溶胶-凝胶法,以异丙醇铝为铝源,考察了不同介质、模板剂种类及用量、煅烧温度等对介孔结构及氧化铝形貌的影响。研究结果表明:在水介质中,以离子液体[Bmim]PF_6为模板剂合成了有序的介孔氧化铝;在乙醇介质中,采用不同离子液体([Bmim]PF_6、[Bmim]Tfo、[Bmim]Cl、[Dmim]Cl、[C16mim]Cl)为模板均可获得具有棒状形貌的介孔氧化铝。研究发现离子液体的用量对氧化铝形貌的形成起着关键的作用。在实验基础上,还从微观角度深度揭示了离子液体模板以及离子液体-表面活性剂共模板合成介孔材料的诱导作用机理,对介孔材料形貌及孔结构的调控具有理论指导意义。
[Abstract]:Mesoporous materials are characterized by regular periodic pore structure, highly uniform and relatively large pore size (2-50 nm), large pore volume, high specific surface area and adjustable pore structure. Biomedical synthesis and other fields have been widely used. Ionic liquids with low interfacial tension, good thermal stability, wide liquid range, amphiphilic properties, can form a wide range of hydrogen bonds and have good supramolecular structure, and have been widely used in the field of material synthesis in recent years. In this paper, mesoporous silica and mesoporous alumina were synthesized by using disubstituted imidazole ionic liquids as templates. Finally, mesoporous silica and mesoporous alumina with different morphologies and different pore structures were obtained. On the basis of this, the mechanism of template action in the synthesis of mesoporous materials by ionic liquids was also studied. For the synthesis of mesoporous silica, the effect of the amount and type of template on the pore structure and morphology of the synthesized mesoporous silica was investigated by sol-gel method, using tetraethyl orthosilicate (TEOS) as silicon source and hydrochloric acid as catalyst. The results show that the mesoporous silica materials with wormlike mesoporous structure have been synthesized by using ionic liquid [Bmim] Tfol, [Bmim] Cl and [Bmim] PF6 as templates, respectively. Highly ordered mesoporous silica with double mesoporous structure was synthesized by co-templates of ionic liquid [Bmim] Tfol, [Bmim] Cl and [Bmim] PF6 and P123, respectively. Tubular silicon oxide was synthesized by co-template of [Dmim] Cl and P123. The tube wall is highly ordered mesoporous. For the synthesis of mesoporous alumina, the effects of different media, type and amount of template and calcination temperature on the mesoporous structure and morphology of alumina were investigated by sol-gel method and aluminum isopropanol as aluminum source. The results show that the ordered mesoporous alumina is synthesized by using ionic liquid [Bmim] PF6 as template in aqueous medium, and mesoporous alumina with rod-like morphology can be obtained by using different ionic liquids ([Bmim] PF6, [Bmim] Tfol, [Bmim] Cl, [Dmim] Cl, [C16mim] Cl) as templates in ethanol medium. It is found that the amount of ionic liquid plays a key role in the formation of alumina morphology. On the basis of the experiments, the inductive mechanism of the synthesis of mesoporous materials by ionic liquid template and ionic liquid-surfactant co-template was also revealed from the microcosmic point of view, which is of theoretical significance for the regulation of the morphology and pore structure of mesoporous materials.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.4;O645.1

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