Investigation of the local catalyst distribution in an aged direct methanol fuel cell MEA by means of differential synchrotron X-ray absorption edge imaging with high energy resolution
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- 作者：Tobias Arlt ; Ingo Manke ; Klaus Wippermann ; Heinrich Riesemeier ; J¨¹rgen Mergel ; John Banhart
- 关键词：XAS ; X-ray energy edge ; Membrane electrode assembly ; Direct methanol fuel cell ; Aging mechanism ; X-ray synchrotron radiography
- 刊名：Journal of Power Sources
- 出版年：2013
- 出版时间：1 January, 2013
- 年：2013
- 卷：221
- 期：Complete
- 页码：210-216
- 全文大小：1455 K
文摘
Synchrotron X-ray absorption edge imaging with high energy resolution was applied to study aging of fuel cell catalyst materials. The combination of an imaging and a high X-ray energy resolution set-up allows acquiring spatially resolved XAS (XANES and EXAFS) spectra. We analyzed the two-dimensional distribution of Pt and Ru in fresh and aged fuel cell catalysts. Spatially resolved XAS images were taken at the RuK edge and at the PtL3 edge. Taking radiographs above and below the absorption edges provides quantitative information about the thickness of the catalytic materials and additional chemical information. A strong influence of the flow field channels and the structure of the gas diffusion layers on the thicknesses of the catalytic elements were found: a thinner catalyst layer was found below the ribs of the flow field geometries as well as under crossing points of fiber bundles of the woven gas diffusion layers.