SAXS and USAXS investigation on nanometer-scaled precursors in organic-mediated zeolite crystallization from gelating systems
- Eindhoven Univ. of Technology (Netherlands). Schuit Inst. of Catalysis
- California Inst. of Tech., Pasadena, CA (United States). Div. of Chemistry and Chemical Engineering
The formation of precursor particles in the crystallization of zeolites from gelating systems has been studied using X-ray scattering at small angles. The crystallization of Si-MFI using trimethylene-bis(N-hexyl, N-methyl-piperidinium) as the structure-directing agent shows the formation of two categories of precursors: gel particles and nanometer-scaled primary units. The size of the primary units for the crystallization of Si-MFI is found to be 2.8 nm both for gelating and nongelating systems using different structure-directing agents. Zeolites Si-BEA and Si-MTW have been prepared using the same organic (trimethylene-bis(N-benzyl, N-methyl-piperidinium)) at different concentrations. Primary units with a size of 2.6 nm are found to be present in the synthesis of Si-BEA, while their size is 1.5 nm in the synthesis mixture directing to Si-MTW. The data suggest that the nanometer-scaled primary units are specific for the zeolite topology formed.
- OSTI ID:
- 323701
- Journal Information:
- Chemistry of Materials, Journal Name: Chemistry of Materials Journal Issue: 1 Vol. 11; ISSN CMATEX; ISSN 0897-4756
- Country of Publication:
- United States
- Language:
- English
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