Highly efficient olefin oxidation catalysts based on regular nano-particles of titanium-containing mesoporous molecular sieves.
Highly efficient olefin oxidation catalysts based on regular nano-particles of titanium-containing mesoporous molecular sieves.
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DOI：
10.1016/j.jcis.2010.09.086
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发表时间：
2011-01
影响因子：
9.9
通讯作者：
Yingying Wang;Ge Wang;Mu Yang;Li Tan;W. Dong;R. Luck
中科院分区：
文献类型：
--
作者：
Yingying Wang;Ge Wang;Mu Yang;Li Tan;W. Dong;R. Luck
采用一步合成法和室温二次合成法成功制备了Ti-MCM-41和Ti-MCM-48。用X射线衍射仪、扫描电子显微镜、透射电子显微镜、氮气吸附/脱附等温线和紫外可见光谱对样品进行了表征。结果表明，该催化剂具有有序的介孔结构。钛物种被接枝到纯硅筛骨架中，没有任何证据表明形成了非骨架锐钛矿。在以H_2O_2水溶液为氧化剂的顺环辛烯环氧化反应中，合成后的Ti-MCM-41规则纳米粒子表现出比普通粒子合成后的Ti-MCM-48和Ti-MCM-41更高的转化率和选择性。催化活性的提高可能是由于存在较多的孤立的四配位钛活性中心和规则的纳米粒子，有利于反应物与活性中心的亲和力。
Ti-MCM-41 and Ti-MCM-48 are successfully prepared by one step synthesis and post-synthesis at room temperature. The samples have been characterized by X-ray diffraction, SEM, TEM, nitrogen adsorption/desorption isotherms and UV–Vis spectroscopy. The results demonstrate the existence of an ordered mesoporous structure. The Ti species are grafted into the pure silica sieve frameworks without any evidence of the formation of non-skeleton anatase. The post-synthesis Ti-MCM-41 regular nano-particles display a higher conversion and selectivity as compared to that for both the post-synthesis Ti-MCM-48 and Ti-MCM-41 with ordinary particles, in the epoxidation of cis-cyclooctene with aqueous H2O2as an oxidant. The enhanced catalytic activity may be attributed to the existence of a higher number of isolated tetracoordinated Ti active sites and regular nano-particles, which are conducive to the affinity of the reactants with active sites.