Vinu A, Srinivasu P, Miyahara M, Ariga K
International Center for Young Scientists (ICYS), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan.
J Phys Chem B. 2006 Jan 19;110(2):801-6. doi: 10.1021/jp055851d.
Highly ordered TiSBA-15 mesoporous molecular sieves with different nSi/nTi ratios and tunable pore diameters have been prepared through direct synthesis under various hydrochloric acid concentrations and synthetic temperatures. The structure and the textural parameters of the materials were investigated by powder X-ray diffraction and nitrogen adsorption/desorption measurements. Decrease of the acid concentration and nSi/nTi ratio in the synthetic gel enhanced the amount of Ti incorporation in SBA-15 materials without affecting their structural order and textural parameters. Highly ordered mesoporous TiSBA-15 with a very high Ti content up to a nSi/nTi ratio of 1.9 was prepared for the first time under the optimized synthesis conditions. Control of synthetic temperature resulted in tuning of pore geometries without structural deterioration and Ti content. Ultralarge-pore TiSBA-15 with a pore size of 12.6 nm and a pore volume of 1.3 cm3 g-1 was also synthesized. The nature and the coordination of the Ti atoms in SBA-15 prepared under various synthesis conditions were investigated by UV-vis spectroscopy. It has been found that the Ti atoms are well-dispersed and mostly occupy the tetrahedral coordination under the optimized synthesis conditions. Catalytic performance of the obtained TiSBA-15 materials was also investigated through oxidation of styrene by hydrogen peroxide and tert-butylhydroperoxide as oxidants.
通过在不同盐酸浓度和合成温度下直接合成，制备出了具有不同硅钛比（nSi/nTi）和可调孔径的高度有序的TiSBA - 15介孔分子筛。通过粉末X射线衍射和氮气吸附/脱附测量对材料的结构和织构参数进行了研究。合成凝胶中酸浓度和nSi/nTi比的降低提高了Ti在SBA - 15材料中的掺入量，而不影响其结构有序性和织构参数。在优化的合成条件下首次制备出了硅钛比高达1.9的高Ti含量的高度有序介孔TiSBA - 15。控制合成温度可在不破坏结构和Ti含量的情况下调节孔几何形状。还合成了孔径为12.6 nm、孔体积为1.3 cm³ g⁻¹的超大孔TiSBA - 15。通过紫外可见光谱研究了在各种合成条件下制备的SBA - 15中Ti原子的性质和配位情况。已发现，在优化的合成条件下，Ti原子分散良好，且大多占据四面体配位。还通过以过氧化氢和叔丁基过氧化氢为氧化剂氧化苯乙烯，研究了所得TiSBA - 15材料的催化性能。
