Nano Energy NC_Ar+NH3 is a Fe/N/C electrocatalyst developed by our group to reduce oxygen. It is obtained from the pyrolysis in Ar, then in NH3, of a mixture of ZIF-8 (a metal-organic-framework) and the complex made between ironII acetate and 1,10 phenantroline. In terms of activity and performance, NC_Ar+NH3 is becoming a serious contender to Pt, but it is still unstable in a H2/O2 PEM fuel cell. Its current density recorded at 0.6 V and 80 °C decreases, first quickly during