A\nModified Galvanic\nCell Synthesis of Pd@Pt Core–Shell\nNanowire Catalysts: Structural Insights and Enhanced ORR Performance

One-dimensional nanostructures, specifically\nPd@Pt core–shell\nnanowire catalysts, have garnered significant attention because of\ntheir potential to enhance the sluggish kinetics of the oxygen reduction\nreaction (ORR). However, fully realizing their potential depends on\nachieving consistent and uniform synthesis. In this study, we introduce\nan improved galvanic synthesis method for Pd@Pt core–shell\nnanowire catalysts (Pd-NW@Pt/C) that eliminates the need for electrochemical\ncontrol or reducing agents, making it more accessible and efficient\nthan the traditional Cu underpotential deposition (Cu-UPD) method.\nOur approach ensures a uniform Pt shell, resulting in superior ORR\nactivity, with a mass activity of 1.06 A mg<sub>Pt</sub><sup>–1</sup> and a specific activity of 0.80 mA cm<sub>Pt</sub><sup>–2</sup>. Detailed <i>operando</i> X-ray absorption spectroscopy\n(XAS) measurements, including high-energy resolution fluorescence\ndetection (HERFD-XAS), revealed that Pd-NW@Pt/C catalysts with a fully\ncovered Pt shell exhibit shorter Pt–Pt bond lengths and weaker\noxygen binding energies compared to partially covered Pt shell nanowire\ncatalysts (Pd-NW@Pt/C-ref) and nanoparticle catalysts (Pd-NP@Pt/C),\nleading to significantly enhanced ORR activity. This study demonstrates\nthe effectiveness of a modified galvanic cell method for producing\nhigh-performance Pd@Pt core–shell nanowire catalysts, offering\ninsights into their structural and electronic properties.