Regarding fuel cells, a challenging and important issue are still the catalysts. To a considerable degree, they determine both the performance of stacks and their price. Currently, the most different nanoparticles are being examined in the most different structural combinations. This is also true for the field of water splitting, where catalysts are employed in electrolysis systems. The jury is still out on which materials could ultimately replace platinum in both cases, so work on the required catalyst quantity continues.