%0 Journal Article
%A Kentaro Hansen
%A Priyamvada Goyal
%A Jennifer Garland
%A Andrew R Crothers
%A Ahmet Kusoglu
%B ACS Applied Polymer Materials
%D 2024
%G eng
%N 11
%P 6192–6198
%R 10.1021/acsapm.4c00827
%T Does Confinement Mediate Cerium Exchange and Its Impact on Ionomer Properties?
%U https://pubs.acs.org/doi/10.1021/acsapm.4c00827
%V 6
%! ACS Appl. Polym. Mater.
%X <p><span>Thin-film ionomers, pivotal in the function of fuel-cell catalyst layers (CLs), are undercharacterized compared to their bulk membrane counterparts, especially with respect to cation effects. Cerium cations, used as an additive in fuel-cell membranes, tend to migrate from the membrane into the CL ionomer during operation. This study investigates whether cerium doping of perfluorinated sulfonic acid ionomer changes under confinement (to a nanometer thin film) and affects the hydration behavior. Confinement has a negligible effect on the ionomer’s cerium partitioning, yet it reduces the ionomer water uptake. Thus, cerium replaces protons similarly in a membrane or CL ionomer; however, its presence affects the thermodynamics of hydration differently.</span></p>