Durable electrocatalytic-activity of Pt-Au/C cathode in PEMFCs

Selvaganesh, Vinod S and Selvarani, G and Sridhar, P and Pitchumani, S and Shukla, AK (2011) Durable electrocatalytic-activity of Pt-Au/C cathode in PEMFCs. In: PCCP: Physical Chemistry Chemical Physics, 13 (27). pp. 12623-12634.

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Abstract

Longevity remains as one of the central issues in the successful commercialization of polymer electrolyte membrane fuel cells (PEMFCs) and primarily hinges on the durability of the cathode. Incorporation of gold (Au) to platinum (Pt) is known to ameliorate both the electrocatalytic activity and stability of cathode in relation to pristine Pt-cathodes that are currently being used in PEMFCs. In this study, an accelerated stress test (AST) is conducted to simulate prolonged fuel-cell operating conditions by potential cycling the carbon-supported Pt-Au (Pt-Au/C) cathode. The loss in performance of PEMFC with Pt-Au/C cathode is found to be similar to 10% after 7000 accelerated potential-cycles as against similar to 60% for Pt/C cathode under similar conditions. These data are in conformity with the electrochemical surface-area values. PEMFC with Pt-Au/C cathode can withstand > 10 000 potential cycles with very little effect on its performance. X-ray diffraction and transmission electron microscopy studies on the catalyst before and after AST suggest that incorporating Au with Pt helps mitigate aggregation of Pt particles during prolonged fuel-cell operations while X-ray photoelectron spectroscopy reflects that the metallic nature of Pt is retained in the Pt-Au catalyst during AST in comparison to Pt/C that shows a major portion of Pt to be present as oxidic platinum. Field-emission scanning electron microscopy conducted on the membrane electrode assembly before and after AST suggests that incorporating Au with Pt helps mitigating deformations in the catalyst layer.

Item Type:	Journal Article
Publication:	PCCP: Physical Chemistry Chemical Physics
Publisher:	Royal Society of Chemistry
Additional Information:	Copyright of this article belongs to Royal Society of Chemistry.
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	18 Jul 2011 08:00
Last Modified:	18 Jul 2011 08:00
URI:	http://eprints.iisc.ac.in/id/eprint/39205

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