Engineering Strong Electron Metal–Support Interaction in Ru/W ₂ N/WO _2.72 Heterointerfaces for Efficient Alkaline Hydrogen Evolution

Developing cost-effective electrocatalysts with platinum-like performance for the hydrogen evolution reaction (HER) remains a critical challenge for advancing sustainable energy technologies. Herein, a Ru/W₂N/WO_2.72 (Ru/WNO) heterostructured catalyst is presented in which Ru nanoparticles are anchored at the interface of a conductive W₂N phase and an oxygen-deficient WO_2.72 phase. This tailored interface establishes a bidirectional electronic metal-support interaction (EMSI), where electron donation from W₂N and electron withdrawal by WO_2.72 cooperatively modulate the electronic structure of Ru, stabilizing it in a partially oxidized state. The balanced EMSI environment optimizes hydrogen adsorption and lowers the water dissociation barrier to 0.43 eV, supported by synchrotron X-ray photoelectron spectroscopy and density functional theory calculations. Consequently, Ru/WNO achieves an ultralow overpotential of 21 mV at 10 mA cm^- ² in alkaline media, along with excellent durability exceeding 100 h. This work highlights a rational heterointerface-engineering strategy to manipulate EMSI, offering valuable guidance for developing high-performance and durable HER electrocatalysts.