Rational construction of hierarchical MIL-53/NiCu-LDH heterostructures as electrocatalysts for enhanced oxygen evolution reaction

The development of efficient electrocatalysts through heterostructure engineering is crucial for boosting the oxygen evolution reaction (OER) kinetics. Herein, we demonstrate a hierarchical MIL-53/NiCu-LDH(12) heterostructure in-situ grown on nickel foam (NF), where the MIL-53 component is controllably constructed on NiCu-LDH/NF to establish robust interfacial contact and electronic coupling. This multi-level architecture synergistically endows the catalyst with enlarged electrochemical active surface area, abundant accessible active sites, accelerated electron transfer kinetics, and reduced band gap. Remarkably, operando characterization reveals that the heterojunction undergoes partial structural reconstruction during OER to generate γ-FeOOH/γ-NiOOH active phases. The formed Fe-O-Ni bridging bonds facilitate interfacial charge redistribution, which effectively modulates the electronic configuration and optimizes reaction intermediates adsorption. Benefiting from these merits, the MIL-53/NiCu-LDH(12)/NF electrode delivers exceptional alkaline OER performance, requiring ultralow overpotentials of 160 and 226 mV to achieve current densities of 10 and 100 mA cm −2 , respectively, along with a small Tafel slope of 42 mV dec −1 . This work proposes an innovative strategy integrating hierarchical architecture design with interfacial electronic modulation for developing advanced transition metal-based OER electrocatalysts.