Tuning Microstructures of Iron-Nickel Alloy Catalysts for Efficient Oxygen Evolution Reaction

N-doped carbon(NC) coated iron-nickel alloy catalysts loaded on the carbon fiber papers(CFP) were prepared by firstly hydrothermal depositing iron-nickel based hydroxide/carbonates, then coating dopamine on their surface, and finally annealing the materials. Particularly, the active alloy species can be tuned to be Fe(0.64)Ni(0.36 )and FeNi(3 )and the microscopic structures of the catalysts show to be nanotubes, nanoflowers and nanosheets upon different atomic ratio of Fe2+ to Ni2+. In an alkaline media, the FeNi3@ NC (1 : 3) catalyst exhibits superior oxygen evolution reaction catalytic activities, which only requires an overpotential of 277 mV to reach a current density of 20 mA/cm(2). At the same time, FeNi3@ NC(1 3) displays no obvious activity loss after continuous running for 30 h at 20 mA/cm (2), indicating a good durability. The excellent performances of the alloy catalysts in alkaline solution can be ascribed to their microstructural features : (1) The composites made by NC shell and alloy cores create copious active sites; (2) The NC coating layer prevents the erosion of alloy nanoparticles which thus improves the durability; (3) The three-dimensional structures well promote mass transfer and effectively suppress the gas peeling effect.