Fuel Cell Measurements with Cathode Catalysts of Sputtered Pt₃ Y Thin Films

Fuel cells are foreseen to have an important role in sustainable energy systems, provided that catalysts with higher activity and stability are developed. In this study, highly active sputtered thin films of platinum alloyed with yttrium (Pt₃ Y) are deposited on commercial gas diffusion layers and their performance in a proton exchange membrane fuel cell is measured. After acid pretreatment, the alloy is found to have up to 2.5 times higher specific activity than pure platinum. The performance of Pt₃ Y is much higher than that of pure Pt, even if all of the alloying element was leached out from parts of the thin metal film on the porous support. This indicates that an even higher performance is expected if the structure of the Pt₃ Y catalyst or the support could be further improved. The results show that platinum alloyed with rare earth metals can be used as highly active cathode catalyst materials, and significantly reduce the amount of platinum needed, in real fuel cells.