• • Overpotential of 19 mV at 10 mA cm−2 in alkaline natural seawater: This value is among the lowest reported for Pt-based catalysts, directly reducing the energy input required for industrial-scale seawater electrolysis, where every millivolt saved translates to significant operational cost reductions.
• • Tafel slope of 31 mV dec−1: Indicates a Tafel-limited mechanism with fast HER kinetics, suggesting that the hydroxyl-rich interface accelerates water dissociation and hydrogen adsorption, enabling higher current densities at lower overpotentials compared to conventional PtNi catalysts.
• • Stability over 100 h with only slightly elevated overpotential: Demonstrates resistance to Cl− poisoning and corrosion, addressing the primary failure mode of Pt catalysts in seawater; this durability is critical for continuous hydrogen production without frequent catalyst replacement.
• • Ni vacancies as Lewis acid sites promote transformation of lattice hydroxyls to dissociative hydroxyls: This surface engineering strategy increases hydrophilicity and Cl− resistance, providing a scalable route to enhance catalyst performance without noble metal content increase, potentially lowering material costs.