Binary Layered Double Hydroxide Electrode Array Synthesized via Metal Alloy Corrosion for Oxygen Evolution Reaction

Developing highly efficient and cost-effective anodic electrodes is one of the major challenges in hydrogen evolution via water electrolysis technology. We demonstrate that the chloride corrosion can transform commercial Ni-Fe alloy (invar) into an electrode, revealing a high-efficiency oxygen evolution reaction (OER). The corroded electrode consisted of a dense vertical array of NiFe layered double hydroxide (LDH) nanosheets on the invar foil surface. We discovered that the corrosion rate difference between metallic components of the binary metal serves the growth of the NiFe LDH at the invar surface. This NiFe LDH electrode required an overpotential of 211 mV at a current density of 10 mA/cm²in 1 M KOH, outperforming the commercial IrO₂catalyst by 47 mV. This electrode showed excellent activity against OER owing to their high intrinsic electrical conductivity of direct growth and high electrochemical surface area of NiFe LDH nanosheets. Furthermore, this electrode exhibited excellent electrochemical stability without decay in performance for 7 days at the current density of 50 mA/cm². This study provides rationally designed electrocatalysts with high and stable catalytic activity to obtain a convenient route to the large-scale production of OER electrodes.