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NMR investigation of water and methanol mobility in nanocomposite fuel cell membranes

NMR investigation of water and methanol mobility in nanocomposite fuel cell membranes Water and methanol transport behavior, morphology, and solvent adsorption of filler-free Nafion membrane, Nafion–SiO2, Nafion–TiO2, and two Nafion–Zr(HPO4)2 composites were investigated using nuclear magnetic resonance methods, including spin-lattice relaxation and pulsed-field-gradient spin-echo diffusion conducted under both variable temperature and variable hydrostatic pressure conditions and scanning electron microscopy analysis. A comparison between water and methanol self-diffusion coefficients reveals that the water mobility is higher than the methanol mobility in all the membranes. Additionally, the inclusion of inorganic fillers improves both the solvent uptakes and the transport properties of the composite membranes relative to filler-free Nafion, with the exception of one of the Nafion–Zr(HPO4)2 composite. Nafion–Zr(HPO4)2 composites were prepared by two different procedures, in situ and ex situ. Although phosphorus-31 magic-angle spinning nuclear magnetic resonance spectra show the same structures of the particles in both kinds of membranes, the morphology, solvent absorption properties, and solvent mobilities are very different. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Ionics Springer Journals

NMR investigation of water and methanol mobility in nanocomposite fuel cell membranes

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References (28)

Publisher
Springer Journals
Copyright
Copyright © 2007 by Springer-Verlag
Subject
Chemistry; Electrochemistry; Renewable and Green Energy; Optical and Electronic Materials; Condensed Matter Physics; Energy Storage
ISSN
0947-7047
eISSN
1862-0760
DOI
10.1007/s11581-007-0178-8
Publisher site
See Article on Publisher Site

Abstract

Water and methanol transport behavior, morphology, and solvent adsorption of filler-free Nafion membrane, Nafion–SiO2, Nafion–TiO2, and two Nafion–Zr(HPO4)2 composites were investigated using nuclear magnetic resonance methods, including spin-lattice relaxation and pulsed-field-gradient spin-echo diffusion conducted under both variable temperature and variable hydrostatic pressure conditions and scanning electron microscopy analysis. A comparison between water and methanol self-diffusion coefficients reveals that the water mobility is higher than the methanol mobility in all the membranes. Additionally, the inclusion of inorganic fillers improves both the solvent uptakes and the transport properties of the composite membranes relative to filler-free Nafion, with the exception of one of the Nafion–Zr(HPO4)2 composite. Nafion–Zr(HPO4)2 composites were prepared by two different procedures, in situ and ex situ. Although phosphorus-31 magic-angle spinning nuclear magnetic resonance spectra show the same structures of the particles in both kinds of membranes, the morphology, solvent absorption properties, and solvent mobilities are very different.

Journal

Ionics – Springer Journals

Published: Nov 25, 2007

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