Boosting the durability of RuO<sub>2</sub> via confinement effect for proton exchange membrane water electrolyzer.

Zheng, Wen-Xing; Cheng, Xuan-Xuan; Chen, Ping-Ping; Wang, Lin-Lin; Duan, Ying; Feng, Guo-Jin; Wang, Xiao-Ran; Li, Jing-Jing et al. · Nat Commun · 2025

basic_science · Level V

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Abstract

Ruthenium dioxide has attracted extensive attention as a promising catalyst for oxygen evolution reaction in acid. However, the over-oxidation of RuO<sub>2</sub> into soluble H<sub>2</sub>RuO<sub>5</sub> species results in a poor durability, which hinders the practical application of RuO<sub>2</sub> in proton exchange membrane water electrolysis. Here, we report a confinement strategy by enriching a high local concentration of in-situ formed H<sub>2</sub>RuO<sub>5</sub> species, which can effectively suppress the RuO<sub>2</sub> degradation by shifting the redox equilibrium away from the RuO<sub>2</sub> over-oxidation, greatly boosting its durability during acidic oxygen evolution. Therefore, the confined RuO<sub>2</sub> catalyst can continuously operate at 10 mA cm<sup>-2</sup> for over 400 h with negligible attenuation, and has a 14.8 times higher stability number than the unconfined RuO<sub>2</sub> catalyst. An electrolyzer cell using the confined RuO<sub>2</sub> catalyst as anode displays a notable durability of 300 h at 500 mA cm<sup>-2</sup> and at 60 °C. This work demonstrates a promising design strategy for durable oxygen evolution reaction catalysts in acid via confinement engineering.