Revisiting the seed-assisted synthesis of zeolites without organic structure-directing agents: insights from the CHA case.

ABSTRACT: Herein, the crystallization behaviour of the CHA zeolite synthesized via the seed-assisted method and in the absence of an organic structure-directing agent has been revisited. To date, the working hypothesis of the seed-assisted synthesis method is that the parent gel and seed share the common composite building unit (cbu) of the targeted zeolite crystal. In the case of the CHA zeolite, we reveal that the parent gel in the absence of CHA seeds leads to the formation of the MER zeolite, which does not follow the cbu working hypothesis. It appears that smaller, but essential common units, i.e., 4-membered ring (4-MR) aluminosilicate, play a key role, instead of a larger cbu. The parent gel contains 4-MRs, which can grow into MER and/or CHA, depending on several factors, i.e

SUBMITTER: Kadja GTM 

PROVIDER: S-EPMC9049160 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature