Surface SO _x Species Stabilized Metal–Oxygen Bonds in PtNi Nanoalloy for Highly Efficient and Durable Seawater Hydrogen Production

ABSTRACT Regulation of metal–oxygen (M–O) bonds and incorporation of sulfur are promising approaches for designing electrocatalysts for efficient hydrogen production from seawater. However, the durability of these catalysts is limited by the instability of M–O bonds under cathodic conditions and poisoning caused by the uncontrolled introduction of sulfur. In this study, a “killing two birds with one stone” strategy was developed for creating efficient hydrogen production electrocatalysts that involves anchoring PtNi nanoparticles on hydroxyl‐functionalized carbon nanotubes and modifying the surface with SO x species (S‐PtNi/CNTs) via a one‐pot hot‐injection‐combined wet‐chemical synthesis protocol. In this material, hydroxyl‐functionalized CNTs stabilize PtNi through M–O bonding, while SO x species tune the electronic structure of Pt and enhance M–O bond stability. Consequently, S‐PtNi/CNTs exhibits outstanding hydrogen production performance in alkaline seawater, delivering a 5.4‐fold increase in mass activity and a 21‐fold increase in specific activity compared to commercial Pt/C, along with remarkable stability over a 1000‐h operation period. Furthermore, S‐PtNi/CNTs significantly outperform commercial Pt/C in both a photovoltaic‐electrocatalysis electrolyzer and an anion‐exchange‐membrane water electrolysis system. The results of in situ spectroscopy and theoretical calculations confirm that SO x species stabilization of M–O bonds and improved chloride ions resistance are responsible for the superior performance of S‐PtNi/CNTs.