Unveiling the Dual Active Sites of Ni/Co(OH)₂-Ru Heterointerface for Robust Electrocatalytic Alkaline Seawater Splitting

Constructing bifunctional electrocatalysts through the synergistic effect of diverse metal sites is crucial for achieving high-efficiency and steady overall water splitting. Herein, a "dual-HER/OER-sites-in-one" strategy is proposed to regulate dominant active sites, wherein Ni/Co(OH)₂-Ru heterogeneous catalysts formed on nickel foam (NF) demonstrate remarkable catalytic activity for oxygen evolution reaction (OER) as well as hydrogen evolution reaction (HER). Meanwhile, the potentials@10 mA cm^-2 of Ni/Co(OH)₂-Ru@NF for overall alkaline water and seawater splitting are only 1.36 and 1.41 V, respectively, surpassing those of commercial RuO₂@NF and Pt/C@NF. The Ru site is identified as the primary active site for HER by density functional theory (DFT) calculations, while the Co(OH)₂ site displays the minimal rate-determining step energy barrier (RDS) and functions as the main active site for OER. This study offers novel perspectives on the rational utilization of diverse metal species' catalytic capabilities for developing dual active sites multifunctional electrocatalysts.