Highly efficient oxygen reduction reaction catalyst derived from Fe/Ni mixed-metal-organic frameworks for application of fuel cell cathode

An effective route was originally reported to synthesize a series of iron-nickel-nitrogen codoped carbon nanocomposites, derived from bimetallic iron/nickel metal-organic frameworks (Fe/Ni-MOFs) and nitrogen-doped graphene (NG). Notably, bimetallic Fe/Ni-MOFs/NG nanocomposites as oxygen reduction reaction (ORR) catalysts have been for the first time investigated for cathodic materials in fuel cells. Interestingly, Fe/Ni-MOFs are not only as the ORR catalyst itself, but also as the cocatalyst carriers with NG in our work. The Fe/Ni-MOFs/NG-20 exhibits excellent ORR performances with an onset potential of 1.09 V and a limiting current density of 8.56 mA cm^-2 at a rotation rate of 1600 rpm. The remaining relative current density after 12000 s is kept at 93.69%. The Tafel slope value is 58.17 mV dec^-1. Thus, Fe/Ni-MOFs/NG-20 can be as a novel promising ORR catalyst for cathodes in fuel cells and metal-air batteries to solve the problems of sluggish reaction kinetics, low durability, and high costs.