Revealing in-plane movement of platinum in polymer electrolyte fuel cells after heavy-duty vehicle lifetime
- Autori: Khedekar K.; Zaffora A.; Santamaria M.; Coats M.; Pylypenko S.; Braaten J.; Atanassov P.; Tamura N.; Cheng L.; Johnston C.; Zenyuk I.V.
- Anno di pubblicazione: 2023
- Tipologia: Articolo in rivista
- OA Link: http://hdl.handle.net/10447/608435
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.