Water‐Induced Structural Dynamic Process in Molecular Sieves under Mild Hydrothermal Conditions: Ship‐in‐a‐Bottle Strategy for Acidity Identification and Catalyst Modification. (7th September 2020)

• Record Type: Journal Article
• Authors: Sun, Tantan; Xu, Shutao; Xiao, Dong; Liu, Zhiqiang; Li, Guangchao; Zheng, Anmin; Liu, Wenjuan; Xu, Zhaochao; Cao, Yi; Guo, Qiang; Wang, Nan; Wei, Yingxu; Liu, Zhongmin
• Is Part Of: Angewandte Chemie. Volume 132:Number 46(2020)
• Page Start: 20853
• Page End: 20862
• Publication Date: 2020-09-07
• Subjects: acidity -- molecular sieves -- MTO reaction -- structural dynamic process -- water; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202009648
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: Water is the most important substance in nature. Imitating the formation of natural materials, molecular sieves have been synthesized under hydrothermal conditions and applied in industry. Herein, we reveal an unforeseen observation on a very special water‐induced structural dynamic process of these materials. Dynamic and reversible breaking and forming of T‐O‐T bonds in silicoaluminophosphate (SAPO) occurs through interactions between gaseous water and the molecular‐sieve framework under mild hydrothermal conditions and is confirmed by detection of the incorporation of 17 O from H2 17 O into molecular‐sieve framework. Encapsulation of the bulky molecules trimethylphosphine and pyridine (kinetic diameters much larger than the pore size of SAPO‐34) into CHA cavities consolidated the water‐induced dynamic process. Consequently, new insights into the dynamic features of molecular sieves in water are provided. The ship‐in‐a‐bottle strategy based on these findings also open new fields for fine acidity identification and gives extra boost in shape‐selective catalysis. Abstract : Water‐induced structural dynamic and reversible breaking and forming of T‐O‐T bonds in a molecular sieve under mild hydrothermal conditions offers the potential to widen their range of applications. As a result, a novel ship‐in‐a‐bottle strategy for acidity identification and catalyst modification by introducing bulky probe molecules into a small‐pore‐cavity molecular sieve could be developed.