Trace Ru‐Doped PtCuRu@PtRu Core‐Shell Electrocatalyst for CO‐Resilient Methanol Oxidation

ABSTRACT To overcome the limited water dissociation capability and transition metal dissolution in Pt‐based binary alloys during methanol oxidation reaction (MOR), a PtCuRu‐0.05@PtRu core‐shell electrocatalyst with trace Ru doping was synthesized via liquid‐phase reduction followed by in‐situ electrochemical dealloying. The design leverages three synergistic mechanisms: oxophilic Ru sites in the Pt‐rich shell facilitate water dissociation to generate *OH for efficient *CO oxidation; lattice mismatch between the ternary PtCuRu core and trace Ru‐doped Pt‐rich shell induces compressive strain, downshifting the Pt d ‐band center to weaken *CO adsorption; and the Pt‐rich shell acts as a diffusion barrier suppressing Cu dissolution. As a result, PtCuRu‐0.05@PtRu delivers the highest mass activity of 1.208 A mg _Pt ⁻¹ , surpassing PtCu@Pt and commercial Pt/C samples. Moreover, PtCuRu‐0.05@PtRu exhibits superior durability, maintaining the highest current density during 3600 s chronoamperometry and showing only 3.31% activity decay after five consecutive stability tests (18,000 s), with preserved structural integrity. This work provides a viable strategy for simultaneously enhancing MOR activity and durability via synergistic composition and structure engineering.