Perfluorosulfonic acid (PFSA)-based ionomers, most notably Nafion, provide the ionic connection between catalyst particles and solid polymer ion conducting membrane separators in polymer electrolyte membrane fuel cells (PEMFCs). While necessary, their presence adversely impacts the performance of the catalyst. PEMFC catalyst performance losses associated with Nafion ionomers are due to physical barriers to reactant gas transport and loss of active sites through specific adsorption of polymer-bound sulfonate groups on the catalyst surface. These impacts are particularly damaging for PEMFC high current density (HCD) performance. Here, we show that ionic liquids (IL) present at the catalyst interface can act to prevent the specific adsorption of sulfonate groups of Nafion on Pt surfaces, negating the detrimental impact of the ionomer on reaction rates, specifically for the oxygen reduction reaction (ORR). This result holds promise for further Pt loading reductions in PEMFCs.