Ni/Co Bimetallic Nanoparticles on Co ₃ O ₄ Nanoarrays Bridged by CNTs for High Oxygen Evolution Reaction

Herein, we report a high-performance electrocatalyst for the lattice-oxygen-mediated (LOM) alkaline oxygen evolution reaction (OER), a key process for green hydrogen production. By employing a simple solvothermal and chemical vapor deposition (CVD) approach, we successfully synthesized CNT-bridged Ni/Co bimetallic nanoparticles on a Co 3 O 4 nanoarray matrix supported by nickel foam (NF). The in situ grown CNTs and Ni/Co nanoparticles introduce abundant oxygen vacancies (O v ), significantly lowering the Gibbs free energy (Δ G ) of *OOH desorption and enhancing the OER kinetics. Additionally, edge dislocations in Co nanoparticles induce lattice distortion and strain modulation, optimizing electron transfer and boosting catalytic efficiency and stability. As a result, the Ni/Co-CNTs-Co 3 O 4 /NF electrocatalyst achieves an ultralow overpotential of just 133 mV at 10 mA cm –2, maintaining structural integrity and excellent stability over 72 h at 20 mA cm –2 . Theoretical calculations further confirm that Ni/Co nanoparticle incorporation tunes the d-band center, facilitating the adsorption–desorption balance of oxygen-containing intermediates and accelerating the OER process. When integrated into an alkaline electrolyzer, the Ni/Co-CNTs-Co 3 O 4 /NF electrodes demonstrate a remarkably low operating voltage of 1.58 V at 10 mA cm –2 and impressive durability for over 24 h at 20 mA cm –2 . These findings highlight the strong potential of the Ni/Co-CNTs-Co 3 O 4 /NF electrocatalyst for the application of scalable, high-efficiency water splitting technology.