Zhenzhen Zhao, Meichen Jiao, Jiejie Ling, Han Jiang, Yan Gao, Hao Xu, Hai-Qing Li, Jingang Jiang*, Peng Wu*, Le Xu*
Chin. J. Struct. Chem., 2024, 43: 100336. DOI: 10.1016/j.cjsc.2024.100336
September 15, 2024
IWV; NES; Structure transformation; Zeolite porosity
ABSTRACT
Modulation of zeolite porosity,
including the size and type of channel and cage, is essential for catalysis and
separation. Although zeolites with a variety of porous systems have been
synthesized by hydrothermal or post-synthetic routes, there was still a lack of
rational control of zeolite porosity in the range of large to medium pore/cage.
Herein, based on the rational structure building, the structure similarity
between IWV topology with large-pore opening and supercage and NES topology with medium-pore opening and medium cage was
discovered. Based on the guidance of structure building, two IWV-derived daugther zeolites with different framework
compositions, (Si,Ge)-ECNU-31 and (Si,Ge,Al)-ECNU-31, were hydrothermally
prepared with built-in structural weakness due to the presence of a large
amount of framework Ge atoms, which were utilized to prepare ECNU-32 zeolite
with NES topology through subsequent post-synthetic treatment
under controlled condition. It was demonstrated that the parent IWV zeolite with only Ge and Si as framework atoms was
benefit in post-treatment to obtain a highly crystalline NES zeolite. In constrast, the co-existence of framework Al
atoms in (Si,Ge,Al)-ECNU-31 zeolite enhanced its hydrothermal stability in
water. However, the treatment with acid and amine solutions caused the partial
collapse of zeolite structure. Our results demonstrated that rational selection
of the framework composition and post-synthetic parameters were crucial for the
transformation of large-pore zeolite to medium-pore zeolite.