Water‐Induced Structural Dynamic Process in Molecular Sieves under Mild Hydrothermal Conditions: Ship‐in‐a‐Bottle Strategy for Acidity Identification and Catalyst Modification

Abstract

Water is the most important and universal substance in nature. People have been striving to pursue and discover water‐related processes and imitate these important discoveries for the benefit of mankind. As a successful example of human imitating the formation of natural materials, molecular sieves have been synthesized under hydrothermal condition 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 breakage‐bonding of T‐O‐T bonds in silicoaluminophosphate (SAPO) occurs due to interactions between gaseous water and molecular sieve framework under mild hydrothermal conditions and is confirmed by successful detection of the incorporation of 17 O from H 2 17 O into molecular sieve framework. Successfully encapsulation of 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 sieve in the atmosphere of water are provided. The ship‐in‐a‐bottle strategy based on these findings also open new fields for fine acidity identification and give extra boost in shape‐selective catalysis.