Fabrication of NiCu interconnected porous nanostructures for highly selective methanol oxidation coupled with hydrogen evolution reaction

Electrocatalytic water electrolysis is the most promising clean and efficient process for pure and clean generation of hydrogen. However, water oxidation reaction requires a large overpotential owing to its slow kinetics, causing a lower efficiency of hydrogen production and high energy consumption. Herein, we report the bimetallic NiCu interconnected porous nanostructures on copper foil (NiCu@Cu) prepared by hydrogen bubbles templating electrodeposition technique for methanol oxidation reaction (MOR), which replaces the kinetically sluggish water oxidation reaction and enhances the hydrogen production with lower energy input. With their high macroporosity, interconnected growth on copper foil with excellent conductivity and easy flow of electrolyte on electrode interface, and stabilization of active sites due to bimetallic synergistic effects, the NiCu@Cu electrocatalysts exhibit outstanding activities for HER and MOR. The NiCu@Cu requiring just 1.32 V anodic potential vs RHE at 10 mA cm⁻² for MOR which is significantly lower than that for water oxidation reaction. Moreover, the electrolyzer using NiCu@Cu/NiCu@Cu for anodic MOR and cathodic H₂ production only needs a low input voltage of 1.45 V to deliver a current density of 10 mA cm⁻² with impressive durability.