【作者】 龙能兵；

【导师】 张瑞丰；

【作者基本信息】 宁波大学 ， 无机化学， 2010， 硕士

【摘要】 论文研究大孔材料的制备与功能化的新方法,以三维骨架聚合物为整体型模板,通过表面复制模板技术获得具有三维超薄结构的新型大孔SiO₂材料,解决了多孔材料制备中的大尺寸、大孔径、低缺陷和低成本等一系列问题。论文进一步利用大孔SiO₂材料的结构导向作用以及超强毛细管效应,开展了纳米功能材料的原位制备研究,获得了大尺寸、大孔径的TiO₂/SiO₂光催化材料和C/SiO₂复合导电材料。本文的研究工作主要有以下几个部分:1、利用二阶段相分离控制方法制备具有不同孔径的三维骨架结构的聚合物,通过对反应诱导相分离与离子诱导相分离两过程的控制,在1～2μm范围内调节了孔径大小。采用引入金属离子改变固体材料折射率的方法,从定性的角度获得孔径大小及分布与光学窗口波长范围之间的匹配关系,初步解释了其特有的滤光效应。2、以上述聚合物为模板,通过正硅酸四乙酯原位溶胶-凝胶过程并结合高温烧结的方法,获得了新型大孔SiO₂材料,该材料是以三维弯曲延伸的纳米薄层（厚度为20～30 nm）方式构成的宏观体,其孔道所构成的微环境具有无尘空间和微重力状态的特点。通过研究聚合物模板与目标产物之间的关系,优化了表面复制技术,达到批量生产的要求。3、以大孔SiO₂材料为载体制备光催化复合材料。通过钛酸丁酯溶液浸渍、原位水解、煅烧制备出大孔TiO₂/SiO₂材料。研究发现:TiO₂以纳米薄层方式均匀地沉积在SiO₂的三维超薄层上,形成TiO₂/SiO₂/TiO₂三层夹心结构。该复合材料具有较好的光催化活性,当焙烧温度为600℃和TiO₂的负载量为54.5 wt%时其光催化活性最大,对甲基橙溶液的降解速率常数达到1.78 h-1。4、以大孔SiO₂材料为载体制备新型炭复合材料。以聚丙烯腈为碳源,利用丙烯腈溶液渗透、溶剂蒸发、高温炭化处理得到大孔C/SiO₂复合材料。研究表明:炭以薄膜形式包覆在SiO₂薄层上的表面,膜的厚度与宏观的电导率呈现一定的依赖关系。在800℃炭化处理下,丙烯腈浓度为33 wt%且聚合两次后的C/SiO₂的导电性能最佳,其体积电阻约为16Ωcm,炭膜的平均厚度为16 nm,比表面积约为93 m2·g^-1。更多还原

【Abstract】 We found a new method for the preparation and functionalization of macroporous materials in this paper. A large sized macroporous three-dimensional （3D） SiO₂ material has been prepared by using a 3D skeletal polymer as template through surface replica technique. We have solved low cost preparation problems of the large sized macroporous materials and used the SiO₂ as the platform for functional studies. Due to the effects of structure-direction and strong capillarity from the porous silica template, functional Nanomaterials could be in situ synthesized and shaped as a 3D continuous film covering the silica layer. Using SiO₂ as a support, we have prepared TiO₂/SiO₂ catalyst with a better activity for photo-degradation and a novel C/SiO₂ composite with a better electrical conductivity. Details of the research as follows:By adopting a new method which was based on a two-step phase separation to synthesize 3D skeletal polymers materials with different pore sizes and through the control of the reaction induced phase separation and ion induced phase separation, we can adjust the pore sizes in a range of 1-2μm. By changing the refractive index of solid materials through the introduction of ZnSO4 and CdSO4 in polymer matrix, we have established a qualitative relationship between the wavelength range of transmitting light and the pore size with its distribution in a 3D skeleton and presented a fundamental explanation of the new optical phenomenon.A large sized macroporous SiO₂ support was obtained by using a 3D skeletal polymer as template through an in situ sol-gel process of ethyl silicate and a subsequent calcination at a high temperature. This silica materials show typical 3D ultrathin structure and its thickness of silica layer was 20-30 nm, these pore network formed a special microenvironment with two virtues of microgravity and dustless space. After studying the relationship between polymers and SiO₂, We have optimized surface replica technique and reached the batch prodution of SiO₂.Photocatalysis composite were prepared by using the large sized macroporous SiO₂ as support. By immersing the support in a solution of tetrabutyl titanate in cyclohexane followed by in situ hydrolysis in air and a final calcination, TiO₂ was loaded on the surface of the support to provide TiO₂/SiO₂ complexes and the TiO₂ formed 3D continuous thin films sandwiching the central silica thin layer. The TiO₂/SiO₂ catalyst exhibited a better activity for photo-degradation of methyl orange and the highest rate constant of 1.78 h-1 was obtained from the catalyst containing 54.5 wt% of TiO₂ calcined at 600℃. New carbon materials were prepared by using the large sized macroporous SiO₂ as support. A series of large sized and macroporous C/SiO₂ 3D composites could be obtained, by immersing the support in the Acrylonitrile solution undergo a sequent polymerization and a final calcination. The carbon in the composites was shaped as a 3D continuous film covering the silica layer. The thickness of the carbon film was related to the conductivity. When the concentration of acrylonitrile was 33 wt% and Coating twice, the novel C/SiO₂ composite exhibited a better electrical conductivity, which has an volume resistance of 16 ??cm, an average thickness of 16 nm of the carbon films and the BET surface area of 93 m2·g-1.更多还原