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Nafion/polyaniline/silica composite membranes for hydrogen production and purification

Chen, Chih-Yuan and Garnica-Rodriguez, Jairo I and Duke, Mikel and Costa, Roni F Dalla and Dicks, Andrew L and Diniz da Costa, J. C (2007) Nafion/polyaniline/silica composite membranes for hydrogen production and purification. Journal of Power Sources, 166 (2). pp. 324-330. ISSN 0378-7753

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Abstract

This work investigates the characterization and performance of polyaniline and silica modified Nafion membranes. The aniline monomers are synthesized in situ to form a polyaniline film, whilst silica is embedded into the Nafion matrix by the polycondensation of tetraethylorthosilicate. The physicochemical properties are studied by means of X-ray diffraction and Fourier transform infrared techniques and show that the polyaniline layer is formed on the Nafion surface and improves the structural properties of Nafion in methanol solution. Nafion loses its crystallinity once exposed to water and ethanol, whilst the polyaniline modification allows crystallinity to be maintained under similar conditions. By contrast, the proton conductivities of polyaniline modified membranes are 3–5-fold lower than that of Nafion. On a positive note, methanol crossover is reduced by over two orders of magnitude, as verified by crossover limiting current analysis. The polyaniline modification allows the membrane to become less hydrophilic, which explains the lower proton conductivity. No major advantages are observed by embedding silica into the Nafion matrix. The performance of a membrane electrode assembly (MEA) using commercial catalysts and polyaniline modified membranes in a cell gives a peak power of 8 mW cm−2 at 20 °C with 2 M methanol and air feeding. This performance correlates to half that of MEAs using Nafion, though the membrane modification leads to a robust material that may allow operation at high methanol concentration.

Item Type: Article
Uncontrolled Keywords: ResPubID18930, polyaniline, sol–gel modified nafion; methanol crossover; direct methanol fuel cell peak power; membrane electrode assembly
Subjects: Faculty/School/Research Centre/Department > Institute for Sustainability and Innovation (ISI)
FOR Classification > 0904 Chemical Engineering
FOR Classification > 0303 Macromolecular and Materials Chemistry
Depositing User: VUIR
Date Deposited: 10 May 2012 04:10
Last Modified: 06 Feb 2015 02:02
URI: http://vuir.vu.edu.au/id/eprint/3213
DOI: 10.1016/j.jpowsour.2006.12.102
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