Synergistic Composition and Surface Engineering of Ruthenium‐Cobalt Hydroxide Nanowires for Efficient Oxygen Evolution Catalysis

Abstract Developing efficient electrocatalysts that improve the rate‐determining step (RDS) kinetics is crucial to addressing the kinetically sluggish oxygen evolution reaction (OER). This study introduces ruthenium (Ru)‐cobalt(II) hydroxide (Co(OH)₂) electrocatalysts for high‐performance OER by combining compositional and thermodynamic surface engineering. Density functional theory (DFT) is employed to identify the ideal composition, with experimental validation conducted through electrodeposition, enabling facile control over a wide range of compositions for nanowire catalyst synthesis. Pourbaix diagram analysis helps establish precise synthesis conditions for developing surface nanostructures. The optimized Ru‐Co(OH)₂ catalyst demonstrates exceptional performance, achieving overpotentials of 189 mV at 10 mA cm⁻ ² and 292 mV at 50 mA cm⁻ ² , significantly outperforming other compositions. The exceptional electrocatalytic performance can be attributed to two key factors: strengthened OH adsorption energy due to optimal composition, which lowers the energy barrier of the rate‐determining step in the OER, and increased specific surface area resulting from surface nanostructure formation.