Assembly of sub-crystals in macro-scale and construction of composite building units in micro-scale for SAPO-34

The nucleation and growth of SAPO-34 crystal with TEA as single template was monitored with ex situ time-resolved characterization methods. The investigation focused on the evolution of the intermediate phases at different crystallization stages of SAPO-34. The morphology transformation of the inter...

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Bibliographic Details
Published in:Chemistry, an Asian journal an Asian journal, 2018-08
Main Authors: Yuan, Delin, Xing, Aihua, Miao, Ping, Sun, Qi, Cui, Lishan, Wang, Hui, Ma, Linge, Chiang, FuKuo, Kong, Jiechen
Format: Article
Language:English
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Summary:The nucleation and growth of SAPO-34 crystal with TEA as single template was monitored with ex situ time-resolved characterization methods. The investigation focused on the evolution of the intermediate phases at different crystallization stages of SAPO-34. The morphology transformation of the intermediate phases at different crystallization time revealed the unique self-assembly process of the sub-crystals. The cubic SAPO-34 crystals can be constructed by eight pyramidal sub-units. Additionally, the construction order of cha cages and d6r units in the initial crystallization stage was determined. The prior appearance of cha cages than d6r units can be attributed to structure-directing effect of protonated TEA, which charge balanced with the framework negative charge introduced by Si incorporation. A further analysis shows Si species was incorporated into framework by direct participation in the initial crystallization stage and substitution for framework P during the later stage.
ISSN:1861-471X