期刊
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
卷 133, 期 6, 页码 1917-1934出版社
AMER CHEMICAL SOC
DOI: 10.1021/ja1095057
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资金
- National Research Foundation of Korea [R0A-2007-000-20050-0, 2009-0092793]
- Carbon Dioxide Reduction and Sequestration RD Center [16-2008-02-005-01]
- Ministry of Science and Technology of Korea
- POSTECH
- National Research Foundation of Korea [R0A-2007-000-20050-0, 2009-0092793] Funding Source: Korea Institute of Science & Technology Information (KISTI), National Science & Technology Information Service (NTIS)
Aluminosilicate and gallosilicate zeolite syntheses via a charge density mismatch (CDM) approach are compared at intermediate-silica compositions (Si/Me = 5-16, where Me is Al or Ga). With a variation of the crystallization temperature and of the type and/or concentration of alkali metal ions added as a crystallization structure-directing agent (SDA) to tetraethylammonium tetraethylammonium-tetraethylammonium-hexamethonium, and strontium-choline mixed-SDA systems, we were able to obtain 11 different zeolite structures. However, only 5 out of a total 40 pairs of aluminosilicate and gallosilicate synthesis runs at otherwise identical chemical compositions were found to give the same zeolite product with no detectable impurities, suggesting that the structure-directing ability of Ga is quite different from that of Al even in intermediate-silica synthesis conditions. The CDM approach to offretite synthesis led to hexagonal plate-like crystals with aspect ratios lower than 0.3, and UZM-22 exhibited no significant preference of Al substitution for particular tetrahedral sites, especially for site T1, unlike its framework type material ZSM-18. More interestingly, the EU-1 zeolite obtained from an aluminosilicate synthesis mixture containing Li+ as an inorganic crystallization SDA in the tetraethylammonium hexamethonium double-organic additive system has been characterized to locate about half of its Li+ ions in the framework, while the Li distribution over the 10 topologically different tetrahedral sites is nonrandom in nature.
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