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