Defect-Rich, Rose-Shaped Fe₂Ni₁-Metal-Organic Framework Nanoarrays for Efficient Oxygen Evolution Reaction

This article reports an important improvement of the design of high-efficiency and economical catalysts to accelerate the four-electron-proton-coupled oxygen evolution reaction (OER), which is a critical half-reaction in renewable electrolytic water systems. Herein, the Fe₂Ni₁-MOF nanoarrays with various morphologies were in situ-grown on the surface of nickel foam (NF) based on the acetic acid-assisted strategy for oxygen evolution reaction. Under the control of a regulator, the optimized 3A-TDC-MOF nanosheets in OER exhibit superior catalytic activity with an overpotential of 211 mV at 10 mA cm^-2 and a Tafel slope of 40.3 mV dec^-1, attributing to the rose-shaped nanoarray, abundant defect sites, and Fe-Ni bimetallic synergistic effect. Further analysis shows that the superior electrocatalytic performance depends on the formation of active intermediate metal-oxyhydroxide after the ligand chain 2,5-thiophenedicarboxylic is replaced partially by OH^-. The proposed strategy provides further insights into the design of desirable MOF-based electrocatalytic materials.