A series of novel hierarchically porous catalysts with significant micro-meso-macroporous structures constructed from zeolite nanocrystals have been successfully synthesized by a quasi solid state crystallization transformation process using a glycerin medium. These catalysts possess well-defined macropores and interconnected mesopores in the macropore walls which were constructed by selected microporous zeolitic units. A series of products, including hierarchically porous acidic aluminosilicates catalysts and hierarchically heteroatom-doped catalysts have been synthesized successfully by the quasi solid state crystallization transformation process. Hierarchical micro-meso-macroporous acidic catalysts constructed from zeolite ZSM-5 nanocrystals were synthesized using this synthetic system under the effect of a structure directing agent. The final product MMM-ZSM-5(2) presented an exceptional catalytic performance for the cracking of 1,3,5-triisopropylbenzene (TIPB). Hierarchically micro-meso-macroporous acidic catalysts constructed from zeolite Beta nanocrystals have also been synthesized. The acidity properties of the products formed after different crystallization transformation periods were investigated. Furthermore, hierarchically micro-meso-macroporous catalysts with heteroatom-doping into the zeolite architecture were also synthesized by this quasi solid state crystallization transformation process. Hierarchically micro-meso-macroporous catalysts constructed from crystalline titanium-doped silicalite-1(TS-1) were also obtained. The final product MMM-TS-1(3) presented superior catalytic performances both for the epoxidation of styrene and 2,4,6-trimethylstyrene. Finally, hierarchically micro-meso-macroporous catalysts constructed from zirconium-doped silicalite-1 (ZrS-1) nanocrystals were also synthesized successfully. The present work demonstrates that the quasi solid state crystallization transformation process is a facile and versatile method to synthesize micro-meso-macroporous catalysts with high performances in different reactions.
|Date of Award||21 Jan 2011|
|Supervisor||BAO LIAN SU (Supervisor), Shilun QIU (Jury), Peter LODEWYCKX (Jury), Davide BONIFAZI (Jury), Alexandre Leonard (Jury) & Carmela APRILE (Jury)|