Characterization of Nd–MCM-41 obtained by impregnation
Characterization of Nd–MCM-41 obtained by impregnation
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DOI：
10.1016/j.micromeso.2007.12.007
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发表时间：
2008-08
影响因子：
5.2
通讯作者：
E. Caponetti;A. Minoja;M. Saladino;A. Spinella
中科院分区：
文献类型：
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作者：
E. Caponetti;A. Minoja;M. Saladino;A. Spinella
以胶束为模板剂制备了介孔分子筛（MCM-41），并采用等体积浸渍法对其进行了功能化。通过EDX获得了在二氧化硅基质中存在钕的证据。SEM照片显示浸渍并没有明显改变MCM-41的形貌。通过XRD图谱分析证实了六方结构的保持。然而，所观察到的长程有序性的损失，细胞参数的增加和表面积的减少，观察到的气体吸附技术，是由于氧化钕的MCM-41介孔内的引入。通过FT-IR和拉曼光谱，发现二氧化硅骨架的主要特征保持不变。由于浸渍，拉曼技术显示二氧化硅非相互作用的硅烷醇基团的消失和一个新的频带，可以归因于Si-O-Nd键的出现。29 Si {1 H} CP-MAS NMR和29 Si {1 H} MAS NMR谱分析表明，含一个羟基的硅原子减少，不含羟基的硅原子增加，证实了拉曼假说。
Silica mesoporous molecular sieves (MCM-41), prepared by using micelles as template, were functionalized by means of incipient wetness method. Evidence for the neodymium presence in the silica matrix was obtained by means of EDX. SEM micrographs showed that impregnation does not change significantly MCM-41 morphology. The maintenance of the hexagonal structure was confirmed by XRD pattern analysis. However, the observed loss of long-range ordering, the cell parameter increase and the surface area decrease, observed by gas adsorption technique, were attributed to the introduction of neodymium oxide inside the MCM-41 mesochannels. By FT-IR and Raman spectra it was found that the main features of the silica framework are maintained. As consequence of impregnation, Raman technique displayed the disappearance of silica non-interacting silanols groups and the appearance of a new band that can be attributed to the Si–O–Nd linkages. The29Si{1H} CP-MAS NMR and29Si{1H} MAS NMR spectra analysis indicated a decrease of silicon atoms bearing one hydroxyl group and an increase of silicon atoms without hydroxyl groups confirming Raman hypothesis.