Interface engineering breaks both stability and activity limits of RuO<sub>2</sub> for sustainable water oxidation.

Du, Kun; Zhang, Lifu; Shan, Jieqiong; Guo, Jiaxin; Mao, Jing; Yang, Chueh-Cheng; Wang, Chia-Hsin; Hu, Zhenpeng et al. · Nat Commun · 2022

basic_science · Level V

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Abstract

Designing catalytic materials with enhanced stability and activity is crucial for sustainable electrochemical energy technologies. RuO<sub>2</sub> is the most active material for oxygen evolution reaction (OER) in electrolysers aiming at producing 'green' hydrogen, however it encounters critical electrochemical oxidation and dissolution issues during reaction. It remains a grand challenge to achieve stable and active RuO<sub>2</sub> electrocatalyst as the current strategies usually enhance one of the two properties at the expense of the other. Here, we report breaking the stability and activity limits of RuO<sub>2</sub> in neutral and alkaline environments by constructing a RuO<sub>2</sub>/CoO<sub>x</sub> interface. We demonstrate that RuO<sub>2</sub> can be greatly stabilized on the CoO<sub>x</sub> substrate to exceed the Pourbaix stability limit of bulk RuO<sub>2</sub>. This is realized by the preferential oxidation of CoO<sub>x</sub> during OER and the electron gain of RuO<sub>2</sub> through the interface. Besides, a highly active Ru/Co dual-atom site can be generated around the RuO<sub>2</sub>/CoO<sub>x</sub> interface to synergistically adsorb the oxygen intermediates, leading to a favourable reaction path. The as-designed RuO<sub>2</sub>/CoO<sub>x</sub> catalyst provides an avenue to achieve stable and active materials for sustainable electrochemical energy technologies.