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首页> 外文期刊>Catalysis science & technology >Framework-substituted cerium MCM-22 zeolite and its interlayer expanded derivative MWW-IEZ
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Framework-substituted cerium MCM-22 zeolite and its interlayer expanded derivative MWW-IEZ

机译：Framework-substituted铈MCM-22沸石其层间扩大MWW-IEZ导数

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摘要

Framework-substituted cerium MCM-22 zeolites were synthesized with both TEOS and solid silica sources. The Si/Al ratio in the gel was 15/1 with two different Si/Ce ratios equal to 100/1 and 30/1. The products showed high Bronsted acid site concentrations, above 700 mu mol g(-1), that diminished slightly as the Ce content increased. The state of Ce was evaluated by IR and UV-vis spectroscopy. There was no indication of a separate Ce phase and extraframework atoms. Both oxidation states, 3+ and 4+, were present. In contrast to the interlayer expanded form MCM-22-IEZ with Ce exchanged into it, the present MCM-22 did not show oxidation of adsorbed CO. This indicates fundamental differences in the location of Ce, which is outside the framework in the exchanged form. The framework-substituted Ce-MCM-22 became active for CO oxidation after its conversion into the IEZ form and additional exchange of Ce. Textural properties were evaluated by nitrogen adsorption and quasi-equilibrated temperature-programmed desorption and adsorption (QE-TPDA) of hydrocarbons.
机译：Framework-substituted铈MCM-22沸石合成teo和固体二氧化硅来源。两个不同的Si / Ce比率等于100/130/1。浓度,超过700亩摩尔g (1)减少略Ce内容增加。Ce的状态进行了红外和紫外可见光谱学。单独的Ce阶段和extraframework原子。3 + 4 +氧化态,礼物。与层间扩展形式与Ce MCM-22-IEZ交换,现在MCM-22没有显示氧化吸附有限公司这表明基本的差异Ce的位置,这是在框架之外交换形式。对CO氧化后Ce-MCM-22开始活跃其转换成IEZ和额外的形式Ce的交换。由氮吸附和评估quasi-equilibrated程序升温解吸和吸附(QE-TPDA)碳氢化合物。

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