To seed or not to seed? That is the question for zeolite AFI crystallization
4 affiliations
- 1Department of Chemical and Biomolecular Engineering, University of Houston 4226 Martin Luther King Blvd. Houston TX 77204 USA
- 2Department of Chemistry, The University of Utah 315 South 1400 East Salt Lake City Utah 84112-0850 USA
- 3Department of Mechanical and Industrial Engineering, University of Illinois Chicago Illinois 60607 USA
- 4Center for Nanoscale Materials, Argonne National Laboratory Lemont Illinois 60439 USA
Abstract
The use of crystalline seeds in zeolite synthesis has become a more frequent method to achieve outcomes that cannot be obtained in their absence. A subset of zeolite syntheses relies on seed-assisted pathways, yet the fundamental role(s) of seeds is not well understood. Here, we systematically investigate several key factors influencing the crystallization of the all-silica AFI zeolite, which is almost exclusively prepared with zeolite seeds. Prior studies have used only two zeolites, with frameworks CHA or *BEA, as the seed (parent) to produce AFI (daughter) without providing detailed rationalizations for seed selection or mechanistic insights into the parent-to-daughter interzeolite transformations that occur in the presence of amorphous precursors. In this study, we show that AFI crystallization occurs in the presence and absence of seeds. Studies of non-seeded syntheses reveal nonclassical pathways of crystallization where nucleation occurs on the exterior surfaces of amorphous precursors, and the judicious selection of synthesis conditions can reduce crystallization times seven-fold compared to methods reported in literature. For seed-assisted syntheses, we show that the number of seeds can be expanded to a total of seven zeolite frameworks that both promote and accelerate AFI crystallization. Mechanistic pathways of AFI formation are examined using a combination of time-resolved experimental studies, molecular dynamics simulations, and zeolite–zeolite interface modeling, in which we demonstrate that seed crystal surfaces can promote nucleation through multiple routes that include heteroepitaxial growth of AFI as a result of their interaction with amorphous precursors or species in solution. Our findings also highlight the important role of inorganic cations, which is uncommon for syntheses of all-silica zeolites, but is essential for AFI crystallization with notable specificity for certain alkali metals depending on the selected organic structure-directing agent. We further demonstrate the incorporation of tetrahedral boron into the AFI zeolite framework via a non-seeded synthesis; however, attempts to incorporate other heteroatoms were unsuccessful. Overall, these studies emphasize the sensitivity of zeolite AFI synthesis to a broad range of parameters and advance our understanding of parent–daughter relationships in seed-assisted zeolite syntheses.
Related
- Role of coupling and zeolite acidity in the methanol-mediated CO2 conversion to olefins over ZnZrOx-AEI zeolite tandem catalysis
- Special Issue: State of the Art and Future Challenges in Zeolite Catalysts
- In situ XAFS analysis system for high-pressure catalytic reactions and its application to CO2 hydrogenation over a Rh/Y-zeolite catalyst
- Ultrathin ZSM-5 zeolite nanocrystals synthesized from purely inorganic precursors
- Gate-Tailoring with Protons and Metal Cations in a Flexible Zeolite for High-Efficiency Ethylene/Ethane Separation
BibTeX
@article{turizopinilla2026seed,
title = {{To seed or not to seed? That is the question for zeolite AFI crystallization}},
author = {Edgar E. Turizo-Pinilla and Eli Martinez and Carlos Chu-Jon and Siddharth Sundararaman and Subramanian K. R. S. Sankaranarayanan and Valeria Molinero and Jeffrey D. Rimer},
journal = {Chemical Science},
year = {2026},
month = aug,
doi = {10.1039/d6sc03105f},
url = {https://doi.org/10.1039/d6sc03105f},
note = {CC BY-NC 3.0},
}
RIS
TY - JOUR
TI - To seed or not to seed? That is the question for zeolite AFI crystallization
AU - Edgar E. Turizo-Pinilla
AU - Eli Martinez
AU - Carlos Chu-Jon
AU - Siddharth Sundararaman
AU - Subramanian K. R. S. Sankaranarayanan
AU - Valeria Molinero
AU - Jeffrey D. Rimer
PY - 2026
DA - 2026/08/25
JO - Chemical Science
DO - 10.1039/d6sc03105f
UR - https://doi.org/10.1039/d6sc03105f
AB - The use of crystalline seeds in zeolite synthesis has become a more frequent method to achieve outcomes that cannot be obtained in their absence. A subset of zeolite syntheses relies on seed-assisted pathways, yet the fundamental role(s) of seeds is not well understood. Here, we systematically investigate several key factors influencing the crystallization of the all-silica AFI zeolite, which is almost exclusively prepared with zeolite seeds. Prior studies have used only two zeolites, with frameworks CHA or *BEA, as the seed (parent) to produce AFI (daughter) without providing detailed rationalizations for seed selection or mechanistic insights into the parent-to-daughter interzeolite transformations that occur in the presence of amorphous precursors. In this study, we show that AFI crystallization occurs in the presence and absence of seeds. Studies of non-seeded syntheses reveal nonclassical pathways of crystallization where nucleation occurs on the exterior surfaces of amorphous precursors, and the judicious selection of synthesis conditions can reduce crystallization times seven-fold compared to methods reported in literature. For seed-assisted syntheses, we show that the number of seeds can be expanded to a total of seven zeolite frameworks that both promote and accelerate AFI crystallization. Mechanistic pathways of AFI formation are examined using a combination of time-resolved experimental studies, molecular dynamics simulations, and zeolite–zeolite interface modeling, in which we demonstrate that seed crystal surfaces can promote nucleation through multiple routes that include heteroepitaxial growth of AFI as a result of their interaction with amorphous precursors or species in solution. Our findings also highlight the important role of inorganic cations, which is uncommon for syntheses of all-silica zeolites, but is essential for AFI crystallization with notable specificity for certain alkali metals depending on the selected organic structure-directing agent. We further demonstrate the incorporation of tetrahedral boron into the AFI zeolite framework via a non-seeded synthesis; however, attempts to incorporate other heteroatoms were unsuccessful. Overall, these studies emphasize the sensitivity of zeolite AFI synthesis to a broad range of parameters and advance our understanding of parent–daughter relationships in seed-assisted zeolite syntheses.
SN - 2041-6520
SN - 2041-6539
ER -