Embedded Ir─Ru Single‐Atom Alloy with Self‐Limiting Motifs for Sustainable Proton Exchange Membrane Water Electrolysis

Designing acid-stable anodic electrocatalysts with low noble-metal loading is essential for the industrial-scale application of proton exchange membrane water electrolysis (PEMWE). However, existing catalyst systems struggle to fully utilize the intrinsic properties of active sites. Here, a precisely engineered nanocatalyst is unveiled through a hierarchical atomic assembly strategy for synthesis, featuring an ultralow-content Ir─Ru single-atom alloy integrated into robust titanium dioxide nanowires (Ir₁Ru/TiO₂). This lattice-embedded structure induces the support to reduce the dissolution and excessive oxidation of Ru/Ir sites through strong interfacial coupling, significantly enhancing the corrosion resistance of catalysts. Moreover, atomically dispersed Ir induces the formation of uniquely shortened Ru─O ligand bonds, serving as stable self-limiting motifs, in contrast to the conventional formation of amorphous oxide layers. The Ir₁Ru/TiO₂ catalyst showcases an initial mass activity of 1971.5 A g Ir + Ru - 1 ${\mathrm{g}}_{{\mathrm{Ir + Ru}}}^{ - {\mathrm{1}}}$ , enabling stable operation at 10 mA cm^-2 for over 3200 h and at the rated current density of 2 A cm^-2 for 2000 h in PEMWE.