Platinum-Alloy Cathode Catalyst Degradation in Proton Exchange Membrane Fuel Cells: Nanometer-Scale Compositional and Morphological Changes
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Shao-Horn_Platinum-alloy.pdf
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Author(s)
Chen, Shuo
Gasteiger, Hubert A.
Hayakawa, Katsuichiro
Tada, Tomoyuki
Shao-Horn, Yang
Date Issued
November 2009
Journal
Journal of The Electrochemical Society
Publisher
The Electrochemical Society
Citation
Chen, Shuo, Hubert A. Gasteiger, Katsuichiro Hayakawa, Tomoyuki Tada, and Yang Shao-Horn. Platinum-Alloy Cathode Catalyst Degradation in Proton Exchange Membrane Fuel Cells: Nanometer-Scale Compositional and Morphological Changes. Journal of The Electrochemical Society 157, no. 1 (2009): A82. © 2009 ECS - The Electrochemical Society
Version
Final published version
Abstract
Electrochemical measurements showed an ≈75% Pt surface area loss and an ≈40% specific activity loss for a membrane electrode assembly (MEA) cathode with acid-treated “Pt[subscript 3]Co ” catalyst particles in a H[subscript 2]/N[subscript 2] proton exchange membrane fuel cell after 24h voltage cycling between 0.65 and 1.05V vs reversible hydrogen electrode. Transmission electron microscopy, scanning transmission electron microscopy, associated X-ray energy dispersive spectroscopy, and high angle annular dark-field techniques were used to probe the microstructural changes of the MEA cathode and the compositional changes along the MEA cathode thickness and within individual Pt[subscript x]Co nanoparticles before and after voltage cycling. Further Co dissolution from acid-treated Pt[subscript x]Co particles that leads to an increased thickness of a Pt-enriched surface layer and the development of core/shell Pt[subscript x]Co particles was largely responsible for the reduction in the specific activity of Pt[subscript x]Co nanoparticle after potential cycling. The Pt weight loss associated with the formation of Pt crystallites near the cathode/membrane interface largely contributed to the measured electrochemical surface area loss, while particle growth of the Pt[subscript x]Co particles via Ostwald ripening played a lesser role.
MIT Department
Massachusetts Institute of Technology. Department of Materials Science and Engineering
Massachusetts Institute of Technology. Department of Mechanical Engineering
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DOI of Published Version
https://doi.org/10.1149/1.3258275
