Surface SO<sub>x</sub> Species Stabilized Metal-Oxygen Bonds in PtNi Nanoalloy for Highly Efficient and Durable Seawater Hydrogen Production.

Yu, Fei; Wang, Yi-Yuan; Pan, Wen-Jie; Wu, Lu; Xiao, Yu-Xuan; Yang, Xiong; Zeng, Bo-Jun; Tian, Ge et al. · Adv Mater · 2026

basic_science · Level V

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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<sub>x</sub> 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<sub>x</sub> 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<sub>x</sub> species stabilization of M-O bonds and improved chloride ions resistance are responsible for the superior performance of S-PtNi/CNTs.