Diffusion and Sorption of Methanol and Water in Nafion Using Time-Resolved Fourier Transform Infrared−Attenuated Total Reflectance Spectroscopy
- 31 October 2007
- journal article
- Published by American Chemical Society (ACS) in The Journal of Physical Chemistry B
- Vol. 111 (46), 13221-13230
- https://doi.org/10.1021/jp075178n
Abstract
Direct methanol fuel cells (DMFCs) are promising portable power sources. However, their performance diminishes significantly because of high methanol crossover (flux) in the polymer electrolyte membrane (e.g., Nafion 117) at the desired stoichiometric methanol feed concentration. In this study, the diffusion and sorption of methanol and water in Nafion 117 were measured using time-resolved Fourier transform infrared−attenuated total reflectance (FTIR-ATR) spectroscopy. This technique is unique because of its ability to measure multicomponent diffusion and sorption within a polymer on a molecular level in real time as function of concentration. Both the effective mutual diffusion coefficients and concentrations of methanol and water in Nafion 117 were determined with time-resolved FTIR-ATR spectroscopy as a function of methanol solution concentration. The methanol flux, calculated from FTIR-ATR, matched that determined from a conventional technique (permeation cell) and increased by almost 3 orders of magnitude over the methanol solution concentration range studied (0.1−16 M). Furthermore, the data obtained in this study reveal that the main contribution to the increase in methanol flux is due to methanol sorption in the membrane.Keywords
This publication has 22 references indexed in Scilit:
- Nafion®/poly(vinyl alcohol) blends: Effect of composition and annealing temperature on transport propertiesJournal of Membrane Science, 2006
- Hyflon Ion Membranes for Fuel CellsIndustrial & Engineering Chemistry Research, 2005
- An NMR study of methanol diffusion in polymer electrolyte fuel cell membranesJournal of Membrane Science, 2005
- Methanol diffusion in water swollen ionomer membranes for DMFC applicationsJournal of Membrane Science, 2004
- Multicomponent diffusion of hydrogen-bonding solutes in a polymerAIChE Journal, 2002
- Separating solvation from molecular diffusion in polymersAIChE Journal, 2001
- Solubility and transport behavior of water and alcohols in Nafion™Polymer, 2001
- Equilibrium and diffusion of methanol and water in a nafion 117 membraneAIChE Journal, 2000
- Water and methanol uptake in proton conducting Nafion® membranesSolid State Ionics, 1997
- Methanol and water uptake, densities, equivalental volumes and thicknesses of several uni- and divalent ionic perfluorosulphonate exchange membranes (Nafion-117) and their methanol-water fractionation behaviour at 298 KJournal of Membrane Science, 1992