Hierarchical NiFe-Layered\nDouble Hydroxide Coupled\nwith Bimetallic NiFe-MOF Electrocatalysts for the Oxygen Evolution\nReaction

It is crucial to utilize extremely efficient and economical\ncatalysts\nfor the energy-intensive and kinetically slow oxygen evolution process.\nHere, we fabricated a NiFeLDH coupled with the NiFe-MOF catalyst with\na unique hierarchical structure using a facile and rapid electrodeposition\nand electrochemical activation strategy. With a low overpotential\nof about 187 mV at 10 mA cm<sup>–2</sup>, the NiFeLDH/NiFe-MOF/NF\ndemonstrates exceptional stability for more than 1000 h. Additionally,\nthe produced NiFeLDH/NiFe-MOF/NF could provide high current densities\nof 500 and 1000 mA cm<sup>–2</sup> in 6 M KOH at relatively\nlow overpotentials of 293 and 353 mV, respectively. The construction\nof heterojunctions provides abundant interfacial active sites and\noptimizes catalytic activity by adjusting the surface electronic structure\nand energy levels. This serves to enhance the intrinsic activity of\nthe catalyst. Density functional theory (DFT) calculations further\nprove that the construction of NiFeLDH regulates the band structure\nof metal sites, enhances the catalytic performance for the oxygen\nevolution reaction (OER), and lowers the intermediate medium’s\nadsorption free energy.