Experimental probing of the effect of PFSA ionomer poisoning at different Pt loadings in a PEMFC

The charge-transfer resistance (Rct) in electrochemical impedance spectroscopy (EIS) was applied to investigate the Pt loading effect on Nafion-induced activity suppression in RDE and MEA. Nafion exhibits a stronger poisoning effect at lower Pt loadings observed in both RDE and MEA. The suppression of activity is enhanced as the decline of Pt loading even with the same sulfonate coverage. Moreover, the simultaneous reduction in the working voltage further aggravates the poisoning, especially under low-Pt conditions. Therefore, it is critical to consider Nafion poisoning when constructing MEAs with low platinum loading, take appropriate strategies to alleviate poisoning and achieve high-performance output.