Cu dual-site doping: synergistic enhancement of OER activity through LDH and nickel foam interface engineering

In the field of water electrolysis, the development of low-cost, highly active oxygen evolution reaction (OER) electrocatalysts remains a central focus. A Cu-doped layered double hydroxide (LDH) composite electrode system was successfully constructed on a nickel foam (NF) substrate via a urea hydrothermal synthesis method. Experimental results demonstrate that Cu doping not only participates in LDH formation but also induces surface modification of the NF substrate, creating Cu–Ni interaction zones that enhance synergistic catalytic effects for the OER. Morphological analysis reveals that Cu doping promotes the vertical growth of LDH nanosheets on the three-dimensional porous NF framework, significantly increasing the reactive interfacial area. Electrochemical tests show that the Cu–NiFe LDH/NF-Cu electrode requires only a 241 mV overpotential at a current density of 20 mA cm⁻², with a Tafel slope as low as 96.8 mV dec⁻¹, demonstrating exceptional catalytic activity. Moreover, the catalyst maintains 97.6% of its initial activity after a 10 h stability test. Density functional theory (DFT) calculations further elucidate that Cu doping enhances the intrinsic OER activity by optimizing the adsorption-free energy of the intermediate (*OOH) and reducing the reaction energy barrier. This study provides a new interfacial engineering strategy for designing high-performance LDH-based electrocatalysts.