Degradation mechanism of FeNC electrocatalysts in PEMFCAt present, the increasing demand for renewable sources along with the requirement of reduction of carbon dioxide emissions is one of the greatest challenges for the scientific community. The intermittency of this type of source is the biggest limit to their widespread, although it could be solved by hydrogen. This element is considered one of the most promising means for storing energy and the improvement of the technology related to this element can be the key for the energetic transition. Amongst all, proton exchange membrane fuel cell (PEMFC) is the most hopeful technology to exploit Hydrogen as fuel to produce electrical power.