文献类型：期刊文献

英文题名：Synthesis of hydrothermally stable and long-range ordered Ce-MCM-48 and Fe-MCM-48 materials

作者：Shao, Yaofeng[1]; Wang, Lingzhi[1]; Zhang, Jinlong[1]; Anpo, Masakazu[2]

机构：[1]E China Univ Sci & Technol, Adv Mat Lab, Shanghai 200237, Peoples R China;[2]E China Univ Sci & Technol, Inst Fine Chem, Shanghai 200237, Peoples R China;[3]Osaka Prefecture Univ, Grad Sch Engn, Osaka 5998531, Japan

年份：2005

卷号：109

期号：44

起止页码：20835

外文期刊名：JOURNAL OF PHYSICAL CHEMISTRY B

收录：;EI(收录号：2005499524584);WOS:【SCI-EXPANDED(收录号:WOS:000233342400028)】；

语种：英文

外文关键词：Gels - Hydrothermal synthesis - Ions - Iron - pH effects - Polymerization - Silicates - Thermodynamic stability

摘要：The hydrothermally stable and long-range ordered Ce-MCM-48 and Fe-MCM-48 were conveniently synthesized at 393 K for 24 h by directly adding fluoride ions to the initial gel without posttreatment and pH adjustment. The Ce-MCM-48 with a Si/Ce of 200 and 100, which were prepared by directly adding fluoride ions, could still maintain their mesoporous structures after refluxing in boiling water for 3 days. The incorporation of Ce into MCM-48 could enhance the hydrothermal stability of MCM-48 in the absence of fluoride ions; however, the incorporation of Fe into MCM-48 materials barely improved the hydrothermal stability of MCM-48 materials. The effect of adding NaF was much more efficient in enhancement of hydrothermal stability than that of the incorporation of Ce. The addition of fluoride ions mainly improves the degree of polymerization of silicates. The Ce4(+) ions in Ce-MCM-48 appear to be present partly in tetrahedral coordination in the framework and partly as CeO2 particles on the surface of framework. The Ce positioned on the surface of pore walls and in the framework both provide the protection against water attack.