Department of Applied Chemistry, Faculty of Science & Engineering, Waseda University, Ohkubo 3-4-1, Shinjuku-ku, Tokyo 169-8555, Japan.
J Colloid Interface Sci. 2011 Jul 1;359(1):240-7. doi: 10.1016/j.jcis.2011.03.016. Epub 2011 Mar 10.
Mesoporous silica containing a large amount of isolated Ti was prepared from an alkoxytitanosiloxane precursor through a hard template method. Isopropoxytris(tris-tert-butoxysiloxy)titanium (((i)PrO)TiOSi(O(t)Bu)(3), TS3) was synthesized and TS3 was mixed with mesoporous carbon (CMK-3), a hard template. The mixture was pyrolyzed at 180 °C to form a composite consisting of titanosilica and the hard template. After calcination at 600 °C for the removal of the carbon template, the titanium species were not transformed to anatase TiO(2), proved by DR-UV-Vis, FTIR, XPS, and XRD, while the ESR results indicated the presence of isolated Ti. The mesoporous structure was verified by SEM, TEM, and N(2) adsorption. The Si/Ti ratio of the product was consistent with that of the precursor. All the results show that the material prepared from the precursor is ordered mesoporous silica containing a large amount of isolated Ti in the frameworks. The use of well-defined alkoxytitanosiloxane precursor leads to the formation of mesoporous silica with exactly controlled composition of titanium with neither loss of Ti nor transformation to anatase.
采用硬模板法，由烷氧钛硅氧烷前体制备了含有大量孤立钛的中孔二氧化硅。合成了异丙氧基三(三(叔丁氧基硅氧基)钛(((i)PrO)TiOSi(O(t)Bu)(3), TS3)，并将 TS3 与硬模板介孔碳 (CMK-3) 混合。将混合物在 180°C 下进行热解，形成由钛硅石和硬模板组成的复合材料。在 600°C 下煅烧以除去碳模板后，通过 DR-UV-Vis、FTIR、XPS 和 XRD 证明钛物种未转化为锐钛矿 TiO(2)，而 ESR 结果表明存在孤立的 Ti。通过 SEM、TEM 和 N(2)吸附验证了介孔结构。产物的 Si/Ti 比与前体一致。所有结果表明，由前体制备的材料是有序介孔二氧化硅，其中在骨架中含有大量孤立的钛。使用定义明确的烷氧钛硅氧烷前体制备了具有精确控制钛组成的介孔二氧化硅，既没有钛的损失也没有向锐钛矿的转化。
