In:
ECS Transactions, The Electrochemical Society, Vol. 58, No. 1 ( 2013-08-31), p. 937-943
Abstract:
This study shows that the modifications in structure and composition of Pt 3 Co/C nanoparticles during real life PEMFC operation (3422 hours of operation at T = 70 °C under H 2 /air) is much richer than previously thought from accelerated stress tests. Using aberration-corrected scanning transmission electron microscopy and electron energy-loss spectroscopy, we show that Co atoms are continuously dissolved from the mother electrocatalyst, and that three different metal nanostructures emerge during PEMFC operation: (i) Pt-Co/C core-shell nanoparticles characterized by an alloyed core surrounded by a thick Pt-rich shell, (ii) Pt-Co/C “hollow” nanoparticles and (iii) pure Pt/C “hollow” nanoparticles, from which Co dissolution has been completed. The high surface area carbon support is not stable either, its less organized domains being preferentially corroded, a fast kinetics process that is followed by slower corrosion of its graphitic regions.
Type of Medium:
Online Resource
ISSN:
1938-5862
,
1938-6737
DOI:
10.1149/05801.0937ecst
Language:
Unknown
Publisher:
The Electrochemical Society
Publication Date:
2013
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