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Entrance and diffusion pathway of CO 2 and dimethyl ether in silicalite‐1 zeolite channels as determined by single‐crystal XRD structural analysis
Author(s) -
Fujiyama Shinjiro,
Yoza Kenji,
Kamiya Natsumi,
Nishi Koji,
Yokomori Yoshinobu
Publication year - 2015
Publication title -
acta crystallographica section b
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.604
H-Index - 33
ISSN - 2052-5206
DOI - 10.1107/s2052520615000256
Subject(s) - zeolite , diffusion , adsorption , crystal (programming language) , chemistry , molecule , materials science , crystallography , organic chemistry , thermodynamics , catalysis , physics , computer science , programming language
The entrance and diffusion pathway of CO 2 and dimethyl ether (DME) in MFI‐type zeolite channels were investigated by a selective sealing method using large silicalite‐1 crystals. The MFI‐type zeolite has two kinds of orthogonal channels: straight channels and sinusoidal channels. The mouths of the straight channels are on (010) crystal faces, while those of the sinusoidal channels are on (100) faces. The channel mouths are directly sealed by silicone resin on the (100) and (010) faces so as to restrict the entrance and diffusion pathways to straight and sinusoidal channel pathways, respectively. The locations and loadings of the guest CO 2 and DME molecules are determined by single‐crystal X‐ray diffraction structural analysis. The loadings show the difference of the adsorption rates between the pathways. The straight channel pathway is 4.2 times faster than the sinusoidal channel pathway for the CO 2 , and the sinusoidal channel pathway is 5.1 times faster than the straight channel pathway for the DME. It reveals their dominant pathways and the anisotropy of adsorption. The dominant pathway correlates to the stability of the channel as adsorption sites.