Surface S-Doped Nanostructured RuO<sub>2</sub> and Its Anion Passivating Effect for Efficient Overall Seawater Splitting.

Liu, Yu; Wu, Lu; Wang, Yong; Shen, Le-Wei; Tian, Ge; Cui, Lianmeng; Qin, Ling; Zhou, Liang et al. · ACS Nano · 2025

basic_science · Level V

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Abstract

Electrolysis of seawater for hydrogen (H<sub>2</sub>) production to harvest clean energy is an appealing approach. In this context, there is an urgent need for catalysts with high activity and durability. RuO<sub>2</sub> electrocatalysts have shown efficient activity in the hydrogen and oxygen evolution reactions (HER and OER), but they still suffer from poor stability. Herein, surface S-doped nanostructured RuO<sub>2</sub> (S-RuO<sub>2</sub>) is rationally fabricated for efficient overall seawater splitting. Doping with S enhances the activity (overpotentials of 25 mV for the HER and 243 mV for the OER), long-term durability (1000 h at 100 mA cm<sup>-2</sup>), and achieves nearly 100% Faraday efficiency (FE). Moreover, the S-RuO<sub>2</sub>-based anion exchange membrane seawater electrolyzer requires 2.01 V to reach 1.0 A cm<sup>-2</sup> under demanding industrial conditions. Experimental analysis and theoretical calculations indicate that surface S introduction could lower the valence state of Ru, thereby conferring enhanced activity and stability. Furthermore, the nanostructured S-RuO<sub>2</sub> electrocatalyst is highly protected by the S-doped surface, which repels Cl<sup>-</sup> in alkaline seawater. This investigation presents a feasible strategy for designing RuO<sub>2</sub>-based seawater splitting catalysts with both high performance and good resistance to anodic corrosion.