Self-supported tri-layer NiFe-LDH/GO/Ni3S2 on nickel foam for enhanced and durable alkaline OER

Abstract

Durable oxygen evolution at practical current densities demands electrodes that integrate efficient charge pathways with mechanically coherent interfaces. We report a self-supported tri-layer NiFe-LDH/GO/Ni₃S₂ architecture on Ni foam constructed by sequential sulfurization (Ni₃S₂ backbone), solution-phase GO deposition (π-conjugated wiring/strain buffer), and low-temperature hydrothermal growth of NiFe-LDH nanosheets. XRD, FE-SEM, and XPS verify the stacked phases and mixed Ni/Fe valence typical of catalytically competent (oxy)hydroxides. The tri-layer electrode delivers η₅₀ = 150 mV and η₁₀₀ = 203 mV with a 55 mV·dec⁻¹ Tafel slope, surpassing a GO-free NiFe-LDH/Ni₃S₂ control. Impedance analysis shows the smallest semicircle (lowest R_ct), while non-faradaic CVs yield the largest C_dl/ECSA, correlating the performance gains with multi-interface charge wiring and enhanced active-site accessibility. During CP operation at 50 mA cm⁻² for 300 h, the electrode maintains 100.38% of its initial operating potential with an ultralow potential drift of −0.0195 mV h⁻¹. Crucially, the electrode also exhibits robust durability at a higher current density of 100 mA cm⁻² for 100 h, confirming stable catalytic operation beyond the initial oxidation regime. Collectively, the results outline a generalizable strategy to wire NiFe-LDH nanophases to 3D scaffolds through a conductive sulfide backbone and an atomically thin carbon interlayer, advancing electrode-level design principles for fast and durable alkaline OER.