ABSTRACT
Among the major challenges to be met for a large-scale development of polymer electrolyte membrane fuel cells (PEMFC), the cost issue related to the catalyst price is certainly the one that requires the largest research eff ort. The reason is that the platinum catalyst metal is, up to now, irreplaceable for an efϐicient operation of the cell. Since Pt-free operating fuel cells are far from being demonstrated, the solution is using far less Pt catalyst while keeping active the catalyst reactions at the PEMFC electrodes. The objective is a reduction factor of the Pt quantity used in a cell with a factor more than 10, starting from typical electrode Pt loadings of 0.1-0.3 mg/cm2
as currently achieved with ink technologies to loadings as low as
0.01 mg/cm2. Therefore, two routes of improvement have been intensively investigated since the beginning of the 1980s. The ϐirst route intends to replace the conventional ink technologies used to fabricate the electrodes by better controlled deposition techniques like vacuum deposition or electro-deposition technologies. The second and complementary route consists in using Pt alloy catalysts instead of pure platinum.
