Investigation of the degradation process of non-precious metal catalysts (NPMC) for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEM-FC)
Today, non-precious metal catalysts of type Fe-N-C can reach current densities for the ORR similar to Pt/C even in acidic media. This is rather important in terms of cost savings, as state-of-the art platinum based catalysts contribute by about 25 % to the overall costs of a fuel cell stack.
One main problem, however, is the long term stability that has to be improved. As a first step into this direction this project focusses on the investigation of the degradation process of Fe-N-C catalysts in accelerated stress tests (ASTs). These ASTs mimic either the standard load cycle of a fuel cell car or the start-up and shut-down conditions. Especially the last named are harmful for the catalysts as the applied potential can cause a massive degradation related to carbon oxidation. A fundamental understanding of the degradation process will help to stabilize these catalysts in a next step to enable the preparation of PEM-FC at significant lower costs compared to the current situation.