Manipulating reaction pathway of ruthenium oxide with enhanced performance and stability toward acidic water oxidation

Developing RuO2-based electrocatalysts with high activity and stability for acidic oxygen evolution reaction (OER) is highly desirable but remains a challenge. More critically, strategies for rational manipulation of the reaction pathway of RuO2 from a kinetically favorable but unstable lattice oxygen oxidation mechanism (LOM) pathway to an adsorption evolution mechanism (AEM) pathway are still elusive. Herein, we report the synthesis of Ce-doped RuO2 catalysts with the existence of oxygen vacancies (Ce-RuO2-x). Experimental results and density functional theory (DFT) calculations reveal that Ru valence state is lowered with the formation of Ce-O-Ru local structure, and Ru-O covalency is decreased, which suppress the surface Ru demetallation and lattice oxygen loss, resulting in greatly enhanced durability toward acidic OER. Moreover, the synergistic effect between Ce-O-Ru local structure and oxygen vacancies can be conducive to the stabilization of OOH∗, leading to a manipulated reaction pathway from LOM to AEM and reduced energy barrier of the rate-determining step.