Bilayer Heterostructured Ni₃S₂@Ta-NiFe LDH Cross-Linked Nanosheets for Efficient Oxygen Evolution Reaction

Transition metal layered double hydroxides (LDHs) are effective electrode materials that can address the sluggish kinetics of the oxygen evolution reaction (OER) at the anode during electrocatalytic hydrogen generation from water, but the application of LDHs is expected to make a breakthrough toward high conductivity and stability. In this study, Ni₃S₂ and Ta-doped NiFe LDH composite cross-linked nanosheets were grown on nickel foam (Ni₃S₂@Ta-NiFe LDH/NF). The optimized material exhibited a significantly increased specific surface area, along with excellent OER performance and stability. At 50 and 100 mA cm^-2 in 1 M KOH, the overpotentials are 188.5 and 203.4 mV, respectively, markedly below RuO₂/NF's 300.6 and 339 mV. The material demonstrates excellent durability, maintaining stable performance for 50 h. The high conductivity and stability are further confirmed in the Pt/C and Ni₃S₂@Ta-NiFe LDH-based two-electrode system with excellent activity (1.472 V at 10 mA cm^-2) and sustained durability. Density functional theory (DFT) calculations reveal that the heterostructure of Ni₃S₂ and Ta-NiFe LDH facilitates interfacial charge transfer, thus improving conductivity. Simultaneously, the electron-deficient state of the metal site weakens the strong adsorption of OER intermediates and accelerates OER kinetics. This work offers fresh perspectives on LDH electrocatalyst design and advances sustainable, cost-effective hydrogen production technology, marked by enhanced efficiency and stability.