Characterization of the amorphous phases formed during the synthesis of microporous material AlPO4-5
Characterization of the amorphous phases formed during the synthesis of microporous material AlPO4-5
复制标题
DOI：
10.1016/j.micromeso.2006.08.009
复制
发表时间：
2007-01-05
影响因子：
5.2
通讯作者：
Huang, Yining
中科院分区：
文献类型：
--
作者：
Longstaffe, James G.;Chen, Banghao;Huang, Yining
我们使用多种固态核磁共振技术，结合粉末 X 射线衍射 (XRD) 和拉曼光谱来表征 AlPO4-5 分子筛合成的中间非晶相的结构。通过 P-31 和 Al-27 魔角旋转 (MAS) NMR 跟踪凝胶相的演变作为结晶时间的函数，以获得有关 Al 和 P 原子局部环境的信息，并通过粉末 XRD 检测凝胶样品的长程有序性。我们利用Al-27/P-31双共振技术，如异核相关光谱（HETCOR）来选择P-31-O-Al-27键连接并通过双共振（TRAPDOR）进行布居转移，以获得有关非晶相中P位点缩合程度的信息。 H-1-->P-31 交叉极化 (CP) 用于识别带有羟基的 P 位点。拉曼光谱也用于跟踪孔隙系统的评估。 C-13 CP MAS 光谱提供有关凝胶中模板分子的化学环境的信息。该工作表明，上述技术的结合可以提供有关水热合成过程中形成的非晶相结构的更详细信息。 (C) 2006 Elsevier Inc. 保留所有权利。
We have used several solid-state NMR techniques in conjunction with powder X-ray diffraction (XRD) and Raman spectroscopy to characterize the structure of the intermediate amorphous phases of AlPO4-5 molecular sieve synthesis. The evolution of the gel phases as a function of crystallization time was followed by P-31 and Al-27 magic-angle spinning (MAS) NMR to obtain information on the local environments of Al and P atoms and by powder XRD to detect the long-range ordering of the gel samples. We have utilized Al-27/P-31 double-resonance techniques such as heteronuclear correlation spectroscopy (HETCOR) to select the P-31-O-Al-27 bonding connectivities and transfer of populations by double-resonance (TRAPDOR) to obtain information regarding the degree of condensation for P sites in the amorphous phases. The H-1-->P-31 cross-polarization (CP) was used to identify the P sites with hydroxyl groups attached. Raman spectroscopy was also employed to follow the evaluation of the pore system. The C-13 CP MAS spectra provide information regarding the chemical environment of template molecule in the gel. The work shows that a combination of the above-mentioned techniques can provide more detailed information on the structure of amorphous phases formed during hydrothermal synthesis. (C) 2006 Elsevier Inc. All rights reserved.