Fuel cell heavy-duty vehicles (HDVs) require increased durability of oxygen-reduction-reaction electrocatalysts, making knowledge of realistic degradation mechanisms critical. Here identical-location micro-X-ray fluorescence spectroscopy was performed on membrane electrode assemblies. The results exposed heavy in-plane movement of electrocatalyst after HDV lifetime, suggesting that electrochemical Ostwald ripening may not be a local effect. Development of local loading hotspots and preferential movement of electrocatalyst away from cathode catalyst layer cracks was observed. The heterogeneous degradation exhibited by a modified cathode gas diffusion layer membrane electrode assembly after HDV lifetime was successfully quantified by the identical-location approach. Further synchrotron micro-X-ray diffraction and micro-X-ray fluorescence experiments were performed to obtain the currently unknown correlation between electrocatalyst nanoparticle size increase and loading change. A direct correlation was discovered which developed only after HDV lifetime. The work provides a route to engineer immediate system-level mitigation strategies and to develop structured cathode catalyst layers with durable electrocatalysts.

Khedekar K., Zaffora A., Santamaria M., Coats M., Pylypenko S., Braaten J., et al. (2023). Revealing in-plane movement of platinum in polymer electrolyte fuel cells after heavy-duty vehicle lifetime. NATURE CATALYSIS, 6(8), 676-686 [10.1038/s41929-023-00993-6].

Revealing in-plane movement of platinum in polymer electrolyte fuel cells after heavy-duty vehicle lifetime

Zaffora A.;Santamaria M.;
2023-08-01

Abstract

Fuel cell heavy-duty vehicles (HDVs) require increased durability of oxygen-reduction-reaction electrocatalysts, making knowledge of realistic degradation mechanisms critical. Here identical-location micro-X-ray fluorescence spectroscopy was performed on membrane electrode assemblies. The results exposed heavy in-plane movement of electrocatalyst after HDV lifetime, suggesting that electrochemical Ostwald ripening may not be a local effect. Development of local loading hotspots and preferential movement of electrocatalyst away from cathode catalyst layer cracks was observed. The heterogeneous degradation exhibited by a modified cathode gas diffusion layer membrane electrode assembly after HDV lifetime was successfully quantified by the identical-location approach. Further synchrotron micro-X-ray diffraction and micro-X-ray fluorescence experiments were performed to obtain the currently unknown correlation between electrocatalyst nanoparticle size increase and loading change. A direct correlation was discovered which developed only after HDV lifetime. The work provides a route to engineer immediate system-level mitigation strategies and to develop structured cathode catalyst layers with durable electrocatalysts.
ago-2023
Settore ING-IND/23 - Chimica Fisica Applicata
Khedekar K., Zaffora A., Santamaria M., Coats M., Pylypenko S., Braaten J., et al. (2023). Revealing in-plane movement of platinum in polymer electrolyte fuel cells after heavy-duty vehicle lifetime. NATURE CATALYSIS, 6(8), 676-686 [10.1038/s41929-023-00993-6].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10447/608435
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