Fast and Durable Alkaline Hydrogen Oxidation Reaction at the Electron-Deficient Ruthenium-Ruthenium Oxide Interface.

The slow hydrogen oxidation reaction (HOR) kinetics under alkaline conditions remain a critical challenge for the practical application of alkaline exchange membrane fuel cells. Herein, Ru/RuO in-plane heterostructures are designed with abundant active Ru-RuO interface domains as efficient electrocatalysts for the HOR in alkaline media. The experimental and theoretical results demonstrate that interfacial Ru and RuO domains at Ru-RuO interfaces are the optimal H and OH adsorption sites, respectively, endowing the well-defined Ru(100)/RuO (200) interface as the preferential region for fast alkaline hydrogen electrocatalysis. More importantly, the metallic Ru domains become electron deficient due to the strong interaction with RuO domains and show substantially improved inoxidizability, which is vital to maintain durable HOR electrocatalytic activity. The optimal Ru/RuO heterostructured electrocatalyst exhibits impressive alkaline HOR activity with an exchange current density of 8.86 mA cm and decent durability. The exceptional electrocatalytic performance of Ru/RuO in-plane heterostructure can be attributed to the robust and multifunctional Ru-RuO interfaces endowed by the unique metal-metal oxide domains.