PtRu Clusters Enable Efficient Proton Transfer and Rapid Hydrogen Evolution

Developing highly efficient and durable electrocatalysts for the hydrogen evolution reaction (HER) requires precise regulation of both electronic structure and interfacial reaction kinetics. Herein, we report the synthesis of highly dispersed PtRu clusters anchored on hollow mesoporous carbon spheres (Pt 1 Ru 1 /HMCS) via an organic‐inorganic co‐assembly strategy. Benefiting from strong Pt‐Ru electronic coupling and robust metal‐support interactions, Pt 1 Ru 1 /HMCS exhibit synergistically optimized hydrogen adsorption/desorption behavior and accelerated proton transfer dynamics. In particular, Ru sites play a pivotal role in enriching and ordering interfacial hydronium species, thereby facilitating the rapid generation and directional migration of H* intermediates to the active sites, and establishing a favorable local microenvironment for HER. Density functional theory (DFT) calculations identify Ru as the primary active center with near‐thermoneutral hydrogen binding, while Pt modulates the electronic structure to optimize overall reaction energetics. As a result, Pt 1 Ru 1 /HMCS deliver an ultralow overpotential of 5.3 mV at 10 mA cm −2 , a high turnover frequency of 11.39 H 2 s −1 at 50 mV (≈9.8‐fold higher than commercial Pt/C), and outstanding durability over 100 h without noticeable degradation. This work establishes a strategy that integrates alloy synergy with interfacial water network engineering, providing new insights into designing next‐generation electrocatalysts for efficient energy conversion.