Suppressing Premature Over-Oxidation of NiFe-LDH via Mo–V Modulation for Durable High-Current Oxygen Evolution

Abstract

Developing efficient and durable oxygen evolution reaction (OER) electrocatalysts is critical for industrial alkaline water electrolysis. Here, we fabricated a Mo–V co-doped NiFe layered double hydroxide (NiFeMoV-LDH) electrode on nickel foam to modulate its intrinsic activity and structural stability. Physical and electrochemical evidence indicates that the synergistic incorporation of Mo and V increases the active surface area and accelerates charge-transfer kinetics. XPS analysis indicates higher average static valence states of the Ni and Fe centers, driven by interfacial electronic redistribution. Consequently, the optimized NiFeMoV-LDH electrode delivers low overpotentials of only 260 mV and 291 mV at 100 and 300 mA·cm−2, respectively, with a small Tafel slope of 30.64 mV·dec−1 in 1.0 M KOH. Notably, the electrode demonstrates stable durability for over 350 h at a high current density of 500 mA·cm−2. In situ Raman analysis reveals that the Mo–V synergistic modulation delays the dynamic phase-transition threshold to the active NiOOH phase to 1.43 V, effectively mitigating premature over-oxidation and protecting the host matrix from structural degradation under continuous OER extremes. These insights underscore the efficacy of polymetallic synergistic regulation for designing industrially relevant OER electrodes.