• • RuCuCe achieves an overpotential of only 18 mV at 10 mA cm−2 in 1.0 M KOH, outperforming Ru-Cu-2 (33 mV) and Ru/C (70 mV), indicating superior intrinsic activity for alkaline HER.
• • The apparent activation energy for HER decreases from 47.4 kJ mol−1 (RuCu) to 26.4 kJ mol−1 (RuCuCe), a 44% reduction that directly quantifies the enhanced water dissociation kinetics.
• • RuCuCe maintains stable operation for over 100 h at a high current density of 500 mA cm−2 in a membrane electrode assembly, demonstrating industrial viability for sustained hydrogen production.
• • The incorporation of ~1 at% Ce into RuCu induces charge redistribution and oxophilic sites, which strengthens H2O adsorption and lowers the kinetic energy barrier for the Volmer step, as confirmed by in situ EIS and pH-dependent measurements.