Pulsed field gradient NMR study of surface diffusion in mesoporous adsorbents

被引：23

作者：

Dvoyashkin, Muslim ^{[1
]}

Khokhlov, Alexey ^{[1
]}

Naumov, Sergej ^{[1
]}

Valiullin, Rustem ^{[1
]}

机构：

[1] Univ Leipzig, Dept Interface Phys, D-04103 Leipzig, Germany

来源：

MICROPOROUS AND MESOPOROUS MATERIALS | 2009年 / 125卷 / 1-2期

关键词：

Mesoporous materials; Surface diffusion; Adsorption; Pulsed field gradient NMR; NUCLEAR-MAGNETIC-RESONANCE; HETEROGENEOUS SURFACES; AMORPHOUS MATERIALS; SELF-DIFFUSION; METAL-SURFACES; TEMPERATURE; ADSORBATES; TRANSPORT; LIQUIDS; SILICON;

D O I：

10.1016/j.micromeso.2008.12.005

中图分类号：

O69 [应用化学];

学科分类号：

081704 ;

摘要：

Surface diffusion of n-heptane in two mesoporous adsorbents with different morphologies of the pore network, namely Vycor random porous glass and porous silicon with linear pores, have been studied using pulsed field gradient NMR. The experimentally obtained diffusivities revealed increasing mobility of guest molecules with increasing surface coverage. indicating heterogeneity of the surface properties. The diffusion studies at different temperatures have further confirmed this hypothesis. The activation energies for surface diffusion turned out to be a function of surface coverage. The experimental results obtained are analyzed using a model of surface diffusion taking account of a distribution of the transition rates. (C) 2008 Elsevier Inc. All rights reserved.

引用

页码：58 / 62

页数：5

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