Cell Performance and Durability of Pt/C Cathode Catalyst Covered by Dopamine Derived Carbon Thin Layer for Polymer Electrolyte Fuel Cells

Pt nanoparticles supported on carbons (Pt/C) as the cathode catalyst for polymer electrolyte fuel cells (PEFCs) were modified with dopamine (DA) and heat-treated, and their performance and durability were investigated to test the concept of forming carbon thin layers on Pt surfaces. The coverage of adsorbed sulfonates from ionomer on the Pt surfaces was decreased with increasing the addition amount of DA, and as a consequence, the mass activity was improved. In addition, the retention of electrochemical surface area of Pt and the cell performance after durability test was improved with increasing the DA amount. The cell performance in a high current density region under wet conditions was, however, deteriorated by the modification. Thus, the modification of Pt surfaces by the overlayers is a promising method for improving both the activity and durability of the catalyst, but oxygen transport at the interface between Pt and ionomer remains an issue.