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Hierarchical MFI Zeolites with a Single‐Crystalline Sponge‐Like Mesostructure
Author(s) -
Zhang Yunjuan,
Luo Peng,
Xu Hao,
Han Lu,
Wu Peng,
Sun Huai,
Che Shunai
Publication year - 2018
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201804193
Subject(s) - mesoporous material , alkyl , microporous material , bifunctional , chemical engineering , materials science , catalysis , chemistry , sponge , zeolite , organic chemistry , geology , engineering , paleontology
Single‐crystalline sponge‐like MFI mesoporous zeolites (SSMZs) have been synthesized by using bolaform surfactants with an axial chiral binaphthyl core in the hydrophobic tail and triquaternary ammonium head groups, as bifunctional organic structure‐directing agents (OSDAs). By changing the length of alkyl chain between a triquaternary ammonium head group and a binaphthyl group from 4 to 10 carbons, SSMZs with high specific surface area (382–434 m 2 g −1 ), abundant micropore‐mesopore connectivity, and uniform mesopore diameter (4–10 nm) were obtained. OSDAs with an alkyl chain length of 11 and 12 carbons led to the formation of nanorod‐constructed mesoporous MFI zeolites. A geometrical matching between the cylindrical arrangement of the binaphthyl groups and the zeolitic framework is speculated to be the key factor for the formation of mesoporous zeolites. The SSMZ zeolites, with abundant mesopores beneficial for the diffusion of reactants, exhibited significantly higher catalytic efficiencies than those of the conventional ZSM‐5 with a microcrystal morphology (≈1.5 μm).