Synthesis and properties of lanthanide incorporated mesoporous molecular sieves
Synthesis and properties of lanthanide incorporated mesoporous molecular sieves
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DOI：
10.1006/jcis.1999.6437
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发表时间：
1999-10-15
影响因子：
9.9
通讯作者：
Jaroniec, M
中科院分区：
文献类型：
--
作者：
Araujo, AS;Jaroniec, M
以十六烷基三甲基溴化铵为模板剂，三甲基氢氧化铵为矿化剂，采用水热法合成了含La、Ce的纳米MCM-41分子筛。X-射线衍射和氮气吸附等表征结果表明，合成的材料具有MCM-41类介孔结构。原子吸收和红外光谱研究表明，这些材料中存在La和Ce。La-和CeMCM-41的BET比表面积分别为590和700m(2)/g，中孔平均直径在3.0~3.5 nm之间。由正丁胺吸附测定的总酸度表明，样品具有由弱到强的酸性中心，CeMCM-41的酸性中心强度远高于LaMCM-41。从低压吸附等温线估算的吸附能分布表明，对于含Ce的材料，表面羟基的数量也较高，(C)1999学术出版社。
Nanostructured lanthanum and cerium incorporated MCM-41 molecular sieves were synthesized via a hydrothermal method using cethyltrimethylammonium bromide as template and trimethylammonim hydroxide as mineralizer. Characterization of these materials by X-ray diffraction and nitrogen adsorption indicates that the resulting materials possess an MCM-41-like mesoporous structure. Atomic absorption and infrared spectroscopy studies revealed the presence of La and Ce in these materials. Their BET surface areas were ca. 590 and 700 m(2)/g for La- and CeMCM-41, respectively, whereas the average mesopore diameters were in the range between 3.0 and 3.5 nm. Total acidity determined by n-butylamine adsorption showed that the samples possess from weak to strong acid sites, the strengths of which are much higher for CeMCM-41 than for LaMCM-41. Adsorption energy distributions evaluated from low pressure adsorption isotherms indicate that the amount of surface hydroxyls is also higher for the cerium containing materials, (C) 1999 Academic Press.