Synergistic Stabilization of Pt Single Atoms by Cl and Ru for Industrial‐Scale Current Density Hydrogen Production

Pt single‐atom (SA) catalysts are considered ideal cathodic materials for PEM water electrolysis (PEMWE) due to their excellent atom utilization and tunable local coordination environment, yet their durability for practical applications remains an unresolved challenge. Herein we report the Pt SAs, synergistically stabilized by Cl‐ligand and Ru nanoparticles, exhibit both high activity and durability for hydrogen evolution reaction (HER). A key finding is that the dynamically evolved Pt–Cl–Pt coordination structure protects Pt SAs against aggregation. Theoretical analysis reveals the unique electronic structure of Pt SAs is finely tuned through the synergistic role of Ru and Cl, resulting in a notable stabilization of Pt SAs. PEMWE with such a catalyst at an ultra‐low Pt loading delivers a cell voltage of only 1.66 V at a current density of 1.0 A cm −2 , while maintaining the outstanding electrocatalytic and structural stability of the Pt–Cl–Pt coordination over 1000 h, thus providing an application potential of SA catalysts.