Interaction of water with zeolites: a review
Interaction of water with zeolites: a review
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DOI：
10.1080/01614940.2021.1948301
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发表时间：
2021-04
期刊：
影响因子：
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通讯作者：
D. Resasco;S. Crossley;Bin Wang;Jeffery L. White
中科院分区：
文献类型：
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作者：
D. Resasco;S. Crossley;Bin Wang;Jeffery L. White
摘要水在许多涉及沸石催化剂的热处理和反应条件中普遍存在，但潜在的影响是复杂的。不同类型的水与沸石的相互作用对这些重要催化剂的稳定性、结构/组成和反应性具有深远的影响。本文综述了沸石表面的水吸附和成核机理，以及沸石缺陷、阳离子和骨架外物种的作用。综述了水与不同Si/Al比、拓扑结构和硅醇缺陷水平的沸石相互作用的实验和计算研究实例。根据最新的DFT计算以及SS NMR和其他光谱研究，评估了与汽蒸过程相关的不同步骤，包括Al-O-Si键水解和随后的结构修饰，如脱铝、中孔形成和非晶化。着重阐述了沸石在气相和液相中水的侵蚀机理的差异，以及沸石壁的疏水/亲水性能的影响。同时，水作为改性剂的反应性的各种作用进行了审查和讨论，无论是普通沸石以及稀土或磷改性材料。
ABSTRACT Water is ubiquitous in many thermal treatments and reaction conditions involving zeolite catalysts, but the potential impacts are complex. The different types of water interaction with zeolites have profound consequences in the stability, structure/composition, and reactivity of these important catalysts. This review analyzes the current knowledge about the mechanistic aspects of water adsorption and nucleation on zeolites surfaces and the concomitant role of zeolite defects, cations and extra framework species. Examples of experimental and computational studies of water interaction with zeolites of varying Si/Al ratios, topologies, and level of silanol defects are reviewed and analyzed. The different steps associated with the process of steaming, including the Al-O-Si bond hydrolysis and subsequent structural modifications, such as dealumination, mesopore formation, and amorphization, are evaluated in light of recent DFT calculations, as well as SS NMR and other spectroscopic studies. Differences between the mechanisms of water attack of the zeolite in vapor or liquid phase are highlighted and explained, as well as the effect of hydrophobic/hydrophilic properties of the zeolite walls. In parallel, the various roles of water as modifier of reactivity are reviewed and discussed, both for plain zeolites as well as rare-earth or phosphorous-modified materials.