Organic Additives to Improve Catalyst Performance for High-Temperature Polymer Electrolyte Membrane Fuel Cells

High-temperature polymer electrolyte membrane fuel cells are promising alternatives to low temperature fuel cells, owing to their higher operating temperatures, which allow for easier water management and enhanced catalytic activity. However, their performance suffers from low oxygen solubility in the electrolyte and phosphoric acid poisoning of catalytically active Pt sites. In this work, we developed new organic additives that provide Pi-Pi stacking of the commercially applied carbon support materials as well as variable substitutable functionalities to interact with the Pt nanoparticles. Different electrochemical methods, such as cyclic voltammetry and linear sweep voltammetry, were performed to test the effect of these organic additives on the onset potential, limiting current, and the number of transferred electrons. It is observed that the limiting currents increase for the additive-modified Pt/C samples, whereas the onset potential for significant oxygen reduction reaction activity remains unchanged. We conclude that enhanced oxygen solubility at the electrode/electrolyte interface is the reason for the observed behavior.