• • RuCu/C-200 achieves an overpotential of 9 mV at 10 mA cm−2 for alkaline HER, outperforming Pt/C and many reported Ru-based catalysts, indicating superior intrinsic activity and potential for reducing energy consumption in water electrolysis.
• • The Tafel slope of 19.7 mV dec−1 for HER suggests a Volmer-Tafel mechanism with fast kinetics, enabling efficient hydrogen production at high current densities, which is critical for industrial electrolyzers.
• • The HOR exchange current density of RuCu/C-200 is 4.2 times higher than that of the unannealed sample, demonstrating that oxygen modification significantly enhances HOR kinetics, which is essential for improving the power output of alkaline fuel cells.
• • Mechanistic studies confirm that oxygen modification optimizes HBE and OHBE and promotes strongly hydrogen-bonded interfacial water, providing a rational design principle for developing high-performance Ru-based electrocatalysts for both HER and HOR in alkaline media.