Site‐Specific <i>d</i> ‐Band Center Engineering With Gallium Enabling Efficient and Durable Hydrogen Evolution From Seawater

ABSTRACT The efficiency of the alkaline hydrogen evolution reaction (HER) is fundamentally constrained by the scaling relationship between water dissociation and hydrogen adsorption/desorption steps. To achieve differentiated optimization of the reaction pathway, a Ni‐Ga‐Pt ternary catalyst with function‐partitioned active sites was constructed in this work by introducing Ga. Through Ga mediation, a site‐specific d ‐band center upshift at Ni sites enhanced hydroxyl (OH) adsorption, thereby accelerating water dissociation. Meanwhile, a downshifted d ‐band center by 0.22 eV at Pt sites optimized the hydrogen adsorption energy (ΔG H* ) to a near‐thermoneutral value of −0.08 eV. This synergistic mechanism reduced the water dissociation energy barrier by 24.5%, enabling the catalyst to achieve an ultralow overpotential of 26 mV at 10 mA cm −2 . When integrated into an anion exchange membrane (AEM) electrolyzer using simulated seawater, the Ni‐Ga‐Pt‐based cathode exhibits long‐term stability by maintaining continuous operation at 500 mA cm −2 for over 600 h, while significantly outperforming the Pt/C || NiFeO x ‐based benchmark device—thus highlighting its significant potential for industrial‐scale seawater electrolysis. This study elucidates a d ‐band partitioning strategy from the perspective of orbital hybridization, providing a generalizable approach to the design of efficient and durable multi‐step electrocatalysts.