A point of concern with using non-PGM catalysts is that, not only do they degrade faster than PGM catalysts under harsh conditions, but they also degrade other parts of the fuel cells. This will reduce not only the durability of the catalyst but also the durability of the overall fuel cell. As mentioned before, PGM catalysts have a stronger MSI to minimize the process of Ostwald ripening; however, because non-PGM catalysts such as metal do not possess the strength of MSI that PGM catalysts such as platinum does, its process of Ostwald ripening would be more consequential. Once iron degrades, the Fe 2+ ions will spread throughout the fuel cell, degrading the fuel cell membrane and causing even more degradation beyond the catalyst's degradation, significantly affecting the durability of non-PGM catalysts .