Synthesis of Sn-Beta by hydrothermal method: The role of seeds

Sn-Beta is a good solid Lewis acid catalyst. Seed-assisted hydrothermal synthesis is a popular method for its preparation. However, the mechanism of seeds in the crystallization process is not clear. Here, the role of seeds in the growth of crystal and the influence on the properties of the corresponding products were studied. The seeds and gel was characterized by XRD , SEM, FT-IR and TG. During the crystallization, it was observed that the seeds were partially dissolved and formed seed fragments in the initial stage. Then the seed fragments acted as the core of the crystals and promoted the crystallization process. Seeds greatly decreased the crystal size of the products as compared with the direct hydrothermal method in absence of seeds. The acidity and catalytic performance of Sn-Beta synthesized via seeds route are similar with those of none-seeds method.