The inability of the thermodynamic descriptor to rationalize the ORR activity trend with OHNafion is likely related to the sluggish desorption kinetics of OHNafion and ONafion. Typically, a decrease in binding energy of an adsorbate would enhance its desorption kinetics, as the binding energy and desorption activation energies are positively related via the Brønsted-Evans-Polanyi (BEP) relation. This is not the case for OHNafion. Compared to OHnormal, OHNafion binds to the surface less strongly, however, its desorption kinetics is more sluggish, as evidenced by the asymmetrical adsorption/desorption CV features (Figure ).