Enhanced activity and interfacial durability study of ultra low Pt based electrocatalysts prepared by ion beam assisted deposition (IBAD) method
✍ Scribed by N. Ramaswamy; T.M. Arruda; W. Wen; N. Hakim; M. Saha; A. Gullá; S. Mukerjee
- Publisher
- Elsevier Science
- Year
- 2009
- Tongue
- English
- Weight
- 1019 KB
- Volume
- 54
- Category
- Article
- ISSN
- 0013-4686
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✦ Synopsis
Ultra low loading noble metal (0.04-0.12 mg Pt /cm 2 ) based electrodes were obtained by direct metallization of non-catalyzed gas diffusion layers via dual ion beam assisted deposition (IBAD) method. Fuel cell performance results reported earlier indicate significant improvements in terms of mass specific power density of 0.297 g Pt /kW with 250 Å thick IBAD deposit (0.04 mg Pt /cm 2 for a total MEA loading of 0.08 mg Pt /cm 2 ) at 0.65 V in contrast to the state of the art power density of 1.18 g Pt /kW using 1 mg Pt(MEA) /cm 2 at 0.65 V. In this article we report the peroxide radical initiated attack of the membrane electrode assembly utilizing IBAD electrodes in comparison to commercially available E-TEK (now BASF Fuel Cell GmbH) electrodes and find the pathway of membrane degradation as well. A novel segmented fuel cell is used for this purpose to relate membrane degradation to peroxide generation at the electrode/electrolyte interface by means of systematic pre and post analyses of the membrane are presented. Also, we present the results of in situ X-ray absorption spectroscopy (XAS) experiments to elucidate the structure/property relationships of these electrodes that lead to superior performance in terms of gravimetric power density obtained during fuel cell operation.