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Controlling the competitive growth of zeolite phases without using an organic structure-directing agent. Synthesis of Al-rich *BEA
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SYSNO ASEP 0554273 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Controlling the competitive growth of zeolite phases without using an organic structure-directing agent. Synthesis of Al-rich *BEA Author(s) Pilař, Radim (UFCH-W) RID, ORCID
Morávková, Jaroslava (UFCH-W) RID, ORCID
Sádovská, Galina (UFCH-W) RID, ORCID
Sklenák, Štěpán (UFCH-W) RID, ORCID, SAI
Brabec, Libor (UFCH-W) RID, ORCID
Pastvová, Jana (UFCH-W) RID, ORCID
Sazama, Petr (UFCH-W) RID, ORCIDArticle number 111726 Source Title Microporous and Mesoporous Materials. - : Elsevier - ISSN 1387-1811
Roč. 333, MAR 2022 (2022)Number of pages 9 s. Language eng - English Country NL - Netherlands Keywords Crystallization ; Hydrothermal synthesis ; Mechanisms ; OSDAs-free synthesis ; Zeolite beta Subject RIV CF - Physical ; Theoretical Chemistry OECD category Physical chemistry R&D Projects GA18-20303S GA ČR - Czech Science Foundation (CSF) LM2018124 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) EF16_013/0001821 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) EF18_046/0015586 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) Method of publishing Limited access Institutional support UFCH-W - RVO:61388955 UT WOS 000761870500001 EID SCOPUS 85123897179 DOI 10.1016/j.micromeso.2022.111726 Annotation The synthesis of zeolites without using an organic structure-directing agent (OSDA) offers great environmental and economic advantages. However, the zeolites being formed are not stabilized by the organic molecules and kinetic control of the synthesis ensuring high yield and purity of the phases is challenging for many zeolites. For OSDA-free synthesis of an Al-rich *BEA zeolite, this study shows that the zeolite is formed as a metastable phase that can undergo transformation immediately after completion of its crystallization to form a thermodynamically more stable MOR zeolite according to Ostwald's rule of stages. The OSDA-free zeolite synthesis is a dynamic process in which crystallization and dissolution occur simultaneously. As soon as a thermodynamically more stable MOR zeolite begins to form in the synthesis mixture, its formation causes depletion of the Al and Si from the synthesis mixture, and, because of the desaturation of the synthesis gel, the original *BEA zeolite begins to dissolve rapidly under hydrothermal conditions. The formation of targeted and parasitic zeolite structures is fundamentally affected by the Al and Si sources. Sources of Al and Si with suitable solubility and the presence of stable zeolite *BEA seeds allow kinetic control to direct the exclusive formation of *BEA zeolite up to a relatively high yields. Then, however, the MOR zeolite phase appears in the product and its formation becomes predominant. This study demonstrates the crucial importance of kinetic control for the selective formation of metastable zeolites in the OSDA-free synthesis. Workplace J. Heyrovsky Institute of Physical Chemistry Contact Michaela Knapová, michaela.knapova@jh-inst.cas.cz, Tel.: 266 053 196 Year of Publishing 2023 Electronic address http://hdl.handle.net/11104/0328904
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