Department of Chemical and Biomolecular Engineering, University of California at Berkeley, Berkeley, California 94720, United States.
J Am Chem Soc. 2011 Mar 16;133(10):3288-91. doi: 10.1021/ja111147z. Epub 2011 Feb 22.
New material UCB-1 is synthesized via the delamination of zeolite precursor MCM-22 (P) at pH 9 using an aqueous solution of cetyltrimethylammonium bromide, tetrabutylammonium fluoride, and tetrabutylammonium chloride at 353 K. Characterization by powder X-ray diffraction, transmission electron microscopy, and nitrogen physisorption at 77 K indicates the same degree of delamination in UCB-1 as previously reported for delaminated zeolite precursors, which require a pH of greater than 13.5 and sonication in order to achieve exfoliation. UCB-1 consists of a high degree of structural integrity via (29)Si MAS NMR and Fourier transform infrared spectroscopies, and no detectable formation of amorphous silica phase via transmission electron microscopy. Porosimetry measurements demonstrate a lack of hysteresis in the N(2) adsorption/desorption isotherms and macroporosity in UCB-1. The new method is generalizable to a variety of Si:Al ratios and leads to delaminated zeolite precursor materials lacking amorphization.
新型材料 UCB-1 是通过在 pH 值为 9 的条件下，使用十六烷基三甲基溴化铵、四丁基氟化铵和四丁基氯化铵的水溶液对沸石前驱体 MCM-22（P）进行分层来合成的，反应温度为 353 K。粉末 X 射线衍射、透射电子显微镜和在 77 K 下的氮气物理吸附的表征表明，UCB-1 的分层程度与之前报道的需要 pH 值大于 13.5 且进行超声处理才能实现剥离的分层沸石前驱体相同。UCB-1 通过 (29)Si MAS NMR 和傅里叶变换红外光谱具有高度的结构完整性，并且通过透射电子显微镜没有检测到无定形硅相的形成。孔隙率测量表明，UCB-1 的 N(2)吸附/解吸等温线和大孔中没有滞后现象。该新方法具有普遍性，可以应用于各种 Si:Al 比，并导致无无定形化的分层沸石前驱体材料的形成。
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