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

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 mgPt -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.