Interface engineering breaks both stability and activity limits of RuO(2) for sustainable water oxidation

Designing catalytic materials with enhanced stability and activity is crucial for sustainable electrochemical energy technologies. RuO(2) 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(2) 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(2) in neutral and alkaline environments by constructing a RuO(2)/CoO(x) interface. We demonstrate that RuO(2) can be greatly stabilized on the CoO(x) substrate to exceed the Pourbaix stability limit of bulk RuO(2). This is realized by the preferential oxidation of CoO(x) during OER and the electron gain of RuO(2) through the interface. Besides, a highly active Ru/Co dual-atom site can be generated around the RuO(2)/CoO(x) interface to synergistically adsorb the oxygen intermediates, leading to a favourable reaction path. The as-designed RuO(2)/CoO(x) catalyst provides an avenue to achieve stable and active materials for sustainable electrochemical energy technologies.