Boosting the durability of RuO2 via confinement effect for proton exchange membrane water electrolyzer
W. Zheng, Xuanxuan Cheng, Ping-Ping Chen, Linlin Wang, Ying Duan, Guojin Feng, Xiaoran Wang, Jingjing Li, Chao Zhang, Ziyou Yu, Tong‐Bu Lu
Abstract
Ruthenium dioxide has attracted extensive attention as a promising catalyst for oxygen evolution reaction in acid. However, the over-oxidation of RuO2 into soluble H2RuO5 species results in a poor durability, which hinders the practical application of RuO2 in proton exchange membrane water electrolysis. Here, we report a confinement strategy by enriching a high local concentration of in-situ formed H2RuO5 species, which can effectively suppress the RuO2 degradation by shifting the redox equilibrium away from the RuO2 over-oxidation, greatly boosting its durability during acidic oxygen evolution. Therefore, the confined RuO2 catalyst can continuously operate at 10 mA cm–2 for over 400 h with negligible attenuation, and has a 14.8 times higher stability number than the unconfined RuO2 catalyst. An electrolyzer cell using the confined RuO2 catalyst as anode displays a notable durability of 300 h at 500 mA cm–2 and at 60 °C. This work demonstrates a promising design strategy for durable oxygen evolution reaction catalysts in acid via confinement engineering. Ruthenium dioxide exhibits good activity for the oxygen evolution reaction in acidic conditions but fails to maintain stable performance over long periods. Here, the authors report a confinement strategy that suppresses ruthenium dioxide degradation, enhancing its long-term durability.