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The Dissolution Dilemma for low Pt Loading Polymer Electrolyte Membrane Fuel Cell Catalysts

preprint
submitted on 26.08.2020 and posted on 27.08.2020 by Daniel John Seale Sandbeck, Niklas Mørch Secher, Masanori Inaba, Jonathan Quinson, Jakob Ejler Sørensen, Jakob Kibsgaard, Alessandro Zana, Francesco Bizzotto, Florian D. Speck, Michael T. Y. Paul, Alexandra Dworzak, Carsten Dosche, Mehtap Oezaslan, Ib Chorkendorff, Matthias Arenz, Serhiy Cherevko
Cost and lifetime currently hinder widespread commercialization of polymer electrolyte
membrane fuel cells (PEMFCs). Reduced electrode Pt loadings lower costs; however, the impact
of metal loading (on the support) and its relation to degradation (lifetime) remain unclear. The
limited research on these parameters stems from synthetic difficulties and lack of in situ
analytics. This study addresses these challenges by synthesizing 2D and 3D Pt/C model catalyst
systems via two precise routes and systematically varying the loading. Pt dissolution was
monitored using on-line inductively coupled plasma mass spectrometry (on-line-ICP-MS), while
X-ray spectroscopy techniques were applied to establish the oxidation states of Pt in correlation
with metal loading. Dissolution trends emerge which can be explained by three particle
proximity dependent mechanisms: (1) shifts in the Nernst dissolution potential, (2) redeposition,
and (3) alteration of Pt oxidation states. These results identify engineering limitations, which
should be considered by researchers in fuel cell development and related fields.

History

Email Address of Submitting Author

matthias.arenz@dcb.unibe.ch

Institution

University of Bern

Country

Switzerland

ORCID For Submitting Author

0000-0001-9765-4315

Declaration of Conflict of Interest

no conflict of interest

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