微型多孔材料
魔角纺纱
硅酸铝
选择性
离子交换
方解石
分子筛
固态核磁共振
热稳定性
傅里叶变换红外光谱
催化作用
红外光谱学
材料科学
莫来石
光谱学
吸附
核磁共振波谱
化学工程
化学
沸石
物理化学
离子
有机化学
核磁共振
陶瓷
工程类
物理
量子力学
作者
Jialiang Li,Mingkun Gao,Wenfu Yan,Jihong Yu
出处
期刊:Chemical Science
[The Royal Society of Chemistry]
日期:2023-01-01
卷期号:14 (8): 1935-1959
被引量:28
摘要
Zeolites are typically a class of crystalline microporous aluminosilicates that are constructed by SiO4 and AlO4 tetrahedra. Because of their unique porous structures, strong Brönsted acidity, molecular-level shape selectivity, exchangeable cations, and high thermal/hydrothermal stability, zeolites are widely used as catalysts, adsorbents, and ion-exchangers in industry. The activity, selectivity, and stability/durability of zeolites in applications are closely related to their Si/Al ratios and Al distributions in the framework. In this review, we discussed the basic principles and the state-of-the-art methodologies for regulating the Si/Al ratios and Al distributions of zeolites, including seed-assisted recipe modification, interzeolite transformation, fluoride media, and usage of organic structure-directing agents (OSDAs), etc. The conventional and newly developed characterization methods for determining the Si/Al ratios and Al distributions were summarized, which include X-ray fluorescence spectroscopy (XRF), solid state 29Si/27Al magic-angle-spinning nuclear magnetic resonance spectroscopy (29Si/27Al MAS NMR), Fourier-transform infrared spectroscopy (FT-IR), etc. The impact of Si/Al ratios and Al distributions on the catalysis, adsorption/separation, and ion-exchange performance of zeolites were subsequently demonstrated. Finally, we presented a perspective on the precise control of the Si/Al ratios and Al distributions of zeolites and the corresponding challenges.
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