Composition-Balanced Bi-Metallic MOFs Directly Grown on Nickel Foam for High-Efficiency Oxygen Evolution Reaction

In this paper, the electrocatalytic efficiency of bi-metallic organic framework compounds grown on nickel foam (NF) has been enhanced by adjusting the amount of iron and cobalt precursors. A unique wedge-like morphology was observed in Fe-1-Co-1-MOF. The optimized Fe-1-Co-1-MOF (1:1 of molar ratio of iron to cobalt) exhibits superior catalytic activity to oxygen evolution reaction (OER) performance with a lowest overpotential of only 233 mV at a current density of 10 mA·cm−2 and the higher current density of 400 mA·cm−2 can be provided at overpotential of 264 mV. The Tafel slope in alkaline aqueous solutions was 24.4 mV·dec−1. After 10 h of continuous operation, the catalyst showed only a slight loss of current density at 50 mA·cm−2. This success may be attributed to synergy between the bi-metallic organic framework catalyst and the large pores of conductive nickel foam, as well as the synergistic effect between the two phases molecules of the bi-metallic organic framework metal.