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Issue 10, 2011
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Platinum thin film anodes for solid acid fuel cells

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Abstract

Hydrogen electro-oxidation kinetics at the Pt | CsH2PO4 interface have been evaluated. Thin films of nanocrystalline platinum 7.5–375 nm thick and 1–19 mm in diameter were sputtered atop polycrystalline discs of the proton-conducting electrolyte, CsH2PO4, by shadow-masking. The resulting Pt | CsH2PO4 | Pt symmetric cells were studied under uniform H2-H2O-Ar atmospheres at temperatures of 225–250 °C using AC impedance spectroscopy. For thick platinum films (>50 nm), electro-oxidation of hydrogen was found to be limited by diffusion of hydrogen through the film, whereas for thinner films, diffusion limitations are relaxed and interfacial effects become increasingly dominant. Extrapolation to vanishing film thickness implies an ultimate interfacial resistivity of 2.2 Ω cm2, likely reflecting a process at the Pt | H2(g) interface. Films 7.5 nm in thickness displayed a total electro-oxidation resistivity, [R with combining tilde], of 3.1 Ω cm2, approaching that of Pt-based composite anodes for solid acid fuel cells (1–2 Ω cm2). In contrast, the Pt utilization ([R with combining tilde]−1/Pt loading), 19 S mg−1, significantly exceeds that of composite electrodes, indicating that the thin film approach is a promising route for achieving high performance in combination with low platinum loadings.

Graphical abstract: Platinum thin film anodes for solid acid fuel cells

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Article information


Submitted
03 Jun 2011
Accepted
27 Jul 2011
First published
19 Aug 2011

Energy Environ. Sci., 2011,4, 4230-4238
Article type
Paper

Platinum thin film anodes for solid acid fuel cells

M. W. Louie and S. M. Haile, Energy Environ. Sci., 2011, 4, 4230
DOI: 10.1039/C1EE01889B

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