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ID 34176
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Author
Ueda, Takahiro
Omi, Hironori
Eguchi, Taro
Maeda, Mariko
Miyahara, Michihisa
Aisaku, Nagai
Abstract

The existence of micropores and the change of surface structure in pitch-based hard-carbon in xenon atmosphere were demonstrated using Xe-129 NMR. For high-pressure (4.0 MPa) Xe-129 NMR measurements, the hard-carbon samples in Xe gas showed three peaks at 27, 34 and 210 ppm. The last was attributed to the xenon in micropores (<1 nm) in hard-carbon particles. The NMR spectrum of a sample evacuated at 773 K and exposed to 0.1 MPa Xe gas at 773 K for 24 h showed two peaks at 29 and 128 ppm, which were attributed, respectively, to the xenon atoms adsorbed in the large pores (probably mesopores) and micropores of hard-carbon. With increasing annealing time in Xe gas at 773 K, both peaks shifted and merged into one peak at 50 ppm. The diffusion of adsorbed xenon atoms is very slow, probably because the transfer of molecules or atoms among micropores in hard-carbon does not occur readily. Many micropores are isolated from the outer surface. For that reason, xenon atoms are thought to be adsorbed only by micropores near the surface, which are easily accessible from the surrounding space.

Keywords
amorphous materials
microporous materials
nuclear magnetic resonance (NMR)
Note
Published with permission from the copyright holder.
This is a author's copy,as published in JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS , 2008, volume 69, issue 1, pp147-152.
Publisher URL: http://dx.doi.org/10.1016/j.jpcs.2007.08.010
Direct access to Thomson Web of Science record
Copyright © 2008 Elsevier B. V. All rights reserved.
Published Date
2008-04-01
Publication Title
Journal of Physics and Chemistry of Solids
Volume
volume69
Issue
issue1
Start Page
147
End Page
152
Content Type
Journal Article
language
英語
Refereed
True
DOI
Web of Sience KeyUT
Submission Path
physical_and_theoretical_chemistry/28