In-situ synthesis of hierarchical lamellar ZSM-5 zeolite with enhanced MTP catalytic performance by a facile seed-assisted method

• Published in: Journal of porous materials Vol. 27; no. 5; pp. 1265 - 1275
• Main Authors: Chen, Yan-Hong, Han, Dong-Min, Zhang, Qiang, Cui, Hong-Xia
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.10.2020; Springer Nature B.V
• Subjects: Catalysis; Cetyltrimethylammonium bromide; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Hydrothermal crystal growth; Lamellar structure; Methanol; Molecular structure; Morphology; Physical Chemistry; Porosity; Propylene; Silicon dioxide; Structural hierarchy; Zeolites; Nanosheets; Seeds; CTAB; Hierarchical ZSM-5
• ISSN: 1380-2224; 1573-4854
• DOI: 10.1007/s10934-020-00898-w

A seed-assisted route has been applied to prepare the hierarchical lamellar ZSM-5 zeolite with good porosity and catalytic performance in methanol to propylene (MTP) reaction. In this method, ZSM-5 crystal seeds instead of organic quaternary ammonium were used to direct the formation of ZSM-5 nuclei and conventional surfactant cetyltrimethylammonium bromide (CTAB) employed as the mesoporogen. The process for the formation of hierarchical lamellar ZSM-5, including the effect of the ratio of CTAB/SiO 2 , initial gel aging temperature, synthesis temperature and synthesis time were discussed in detail. The results suggested that mesoporous structure was first obtained and then transformed into MFI structure in-situ during the hydrothermal synthesis process. The obtained hierarchical lamellar ZSM-5 zeolite displays an organized flack-like nanosheet stacks morphology with regular intercrystal mesopores of 3–7 nm, possessing large surface area and mesopore volume. Moreover, the synthesized hierarchical ZSM-5 zeolite has perfect catalyst lifetime in methanol to propylene (MTP) reaction than conventional microporous ZSM-5 zeolite, which could be ascribed to the hierarchical mesoporous structure accommodating more bulky molecules and accessible acid sites in the catalytic reaction.