Impact of Accelerated Stress Tests on the Cathodic Catalytic Layer in a Proton Exchange Membrane (PEM) Fuel Cell Studied by Identical Location Scanning Electron Microscopy

Victor Shokhen, Linnéa Strandberg, Magnus Skoglundh, Björn Wickman

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Platinum is the most used electrocatalyst in proton exchange membrane fuel cells (PEMFCs). Nonetheless, it suffers from various types of degradation. Identical location electron microscopy has previously been used to observe local catalyst changes under accelerated stress tests (ASTs), giving insight into how individual catalyst particles degrade. However, it is important that such studies are carried out under relevant reaction conditions, as these can differ substantially between liquid half-cells and real PEMFC conditions. In this work, a single cell PEMFC was used to study the degradation of a commercial Pt-catalyzed membrane electrode assembly by performing square wave voltage ASTs in a potential range of 0.6 to 1.0 V. Identical location scanning electron microscopy (IL-SEM) was used to follow the degradation of the cathodic catalytic layer (CL) throughout 14,000 AST cycles. From the IL-SEM, we can conclude that the Pt nanoparticles degrade via Ostwald ripening, crystal migration, and coalescence. Small Pt nanoparticles agglomerate to larger particles or dissolve and redeposit to more stable particles, increasing the average particle size during the ASTs. In addition, cross-sectional TEM images show thinning of the ionomer layer during the AST procedure. The IL-SEM technique facilitates observation of local degradation of the CL in real PEMFCs, which will help to understand different degradation mechanisms, allowing for better solutions to be designed.

Original languageEnglish
Pages (from-to)11200-11212
Number of pages13
JournalACS Applied Energy Materials
Issue number9
StatePublished - 26 Sep 2022
Externally publishedYes

Bibliographical note

Funding Information:
This project is financially supported by the Swedish Foundation for Strategic Research (Project No. ARC19-0026) and the Swedish Research Council (Project No. 2018-03927), and it is performed within the Competence Centre for Catalysis, which is hosted by Chalmers University of Technology and financially supported by the Swedish Energy Agency (Project No. 52689-1) and the member companies ECAPS, Johnson Matthey, Perstorp, Powercell, Preem, Scania CV, Umicore, and Volvo Group. Physical characterization was performed at Chalmers Materials Analysis Laboratory (CMAL).

Publisher Copyright:
© 2022 American Chemical Society. All rights reserved.


  • accelerated stress test
  • catalyst deactivation
  • catalytic layer degradation
  • identical location-SEM
  • platinum


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