Synthesis and morphological studies of nanocrystalline MOR type zeolite material.
Synthesis and morphological studies of nanocrystalline MOR type zeolite material.
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DOI：
10.1016/j.jcis.2008.05.058
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发表时间：
2008-09
影响因子：
9.9
通讯作者：
Pankaj Sharma;P. Rajaram;R. Tomar
中科院分区：
文献类型：
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作者：
Pankaj Sharma;P. Rajaram;R. Tomar
采用水热法合成了一系列纳米级丝光沸石（莫尔）类似物，其粒径范围为5 ~ 50 nm。考察了介质碱度、硅源种类等生长参数对莫尔型沸石晶体形貌和晶粒尺寸的影响。通过Brunauer-Emmett-Teller（BET）方法研究比表面积和比容。XRD、SEM、TEM研究表明莫尔型晶体呈纳米级生长。电子衍射图案证实了纳米颗粒的结晶性质，并且它们的索引结果证明该材料是莫尔。这些合成的材料显示微孔以及介孔特性。在使用硅酸钠合成的莫尔材料的情况下，发现介质碱度的增加导致材料的形态和晶体尺寸的变化。对于低浓度的NaOH，微晶的形状是球形的，而在高浓度下，它们是直径为25至50 nm的纳米棒的形状。另一方面，当NaOH浓度增加超过2.0摩尔时，使用原硅酸四乙酯（TEOS）合成的莫尔材料的形态没有变化。
A number of nanosize mordenite (MOR) analogues with particle size ranging from 5 to 50 nm were synthesized by the hydrothermal method. The effect of various growth parameters like: alkalinity of the medium, type of silica source, etc. on crystal morphology and the crystal size of MOR type of zeolites was investigated. Specific surface and micropore volume were investigated by the Brunauer–Emmett–Teller (BET) method. XRD, SEM, TEM studies indicate nanosize growth of the MOR type crystals. Electron diffraction patterns confirm the crystalline nature of the nanoparticles and the results of their indexing prove that the material is MOR. These synthesized materials show microporous as well mesoporous character. In the case of MOR material synthesized using sodium silicate, it was found that an increase in the alkalinity of the medium led to changes in the morphology and crystal size of the material. For low concentrations of NaOH, the crystallites were spherical in shape whereas at high concentrations, they were in the shape of nanorods of diameter 25 to 50 nm. The morphology of the MOR material synthesized using tetraethyl orthosilicate (TEOS), on the other hand, did not change when the NaOH concentration was increased beyond 2.0 molar.