The synthesis of SAPO-34 zeolite for an improved MTO performance: tuning the particle size and an insight into the formation mechanism
Traditional SAPO-34 zeolites synthesized using trimethylamine (TEA) as organic templates have relatively large particle size and limited MTO performance. In this work, SAPO-34 plates have been successfully synthesized using TEA as templates with the presence of polyethylene glycol (PEG) as an assist...
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Published in | Inorganic chemistry frontiers Vol. 8; no. 9; pp. 2315 - 2322 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
London
Royal Society of Chemistry
07.05.2021
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Subjects | |
Online Access | Get full text |
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Summary: | Traditional SAPO-34 zeolites synthesized using trimethylamine (TEA) as organic templates have relatively large particle size and limited MTO performance. In this work, SAPO-34 plates have been successfully synthesized using TEA as templates with the presence of polyethylene glycol (PEG) as an assisted template. Two-step crystallization is utilized in the concentrated gel system to control the particle size in the range of 0.9-1.2 μm. The MTO catalysis shows that the as-synthesized SAPO-34 plates exhibit enhanced catalytic performance. At 99% conversion, it has a catalytic lifetime (326 min) that is eight times longer than that of the conventional sample and 80% selectivity for light olefins. Moreover, the NMR study reveals the distinct crystallization process of SAPO-34 in two gel systems. Different from silicon being the activated species and the crystal center in a normal gel system, the aluminophosphate framework is first generated and then silicon gradually enters to replace Al or P in the concentrated gel system.
Effect of gel systems, additives and crystallization conditions on the size of SAPO-34 and the MTO performance has been studied. |
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Bibliography: | Electronic supplementary information (ESI) available. See DOI 10.1039/d1qi00016k |
ISSN: | 2052-1553 2052-1545 2052-1553 |
DOI: | 10.1039/d1qi00016k |