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<p>Intermetallic compounds (IMCs), distinguished by their ordered atomic arrangements and electronic uniformity, exhibit enhanced physicochemical properties compared to their disordered alloy counterparts. Notably, Pt-based intermetallic alloys, such as PtCu₃, demonstrate exceptional catalytic activity and stability in oxygen reduction reaction (ORR) applications. Conventional methods to induce atomic ordering in random alloy structures typically involve high-temperature annealing, which often leads to particle sintering and diminished catalytic performance. This challenge is further amplified in one-dimensional (1D) nanostructures due to their inherent anisotropic characteristics. Herein, we report a facile wet chemical synthesis approach to produce ultrathin, single-crystalline PtCu₃ alloy nanowires exhibiting the disordered (<i>Fm</i><InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="339_2025_8898_Article_IEq1.gif" Format="GIF" Height="23" Rendition="HTML" Resolution="72" Type="Linedraw" Width="14" /> </InlineMediaObject> <EquationSource Format="TEX">\(\:\stackrel{-}{3}\)</EquationSource> </InlineEquation><i>m)</i> phase and the ordered L1₂ phase (<i>Pm</i><InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="339_2025_8898_Article_IEq1.gif" Format="GIF" Height="23" Rendition="HTML" Resolution="72" Type="Linedraw" Width="14" /> </InlineMediaObject> <EquationSource Format="TEX">\(\:\stackrel{-}{3}\)</EquationSource> </InlineEquation><i>m</i>) at approximately 180&#xa0;°C with precise morphological control. Structural characterization via aberration-corrected scanning transmission electron microscopy (STEM) equipped with high-angle annular dark field (HAADF) detector, coupled with X-ray diffraction analysis, confirms the attainment of ordered atomic arrangements. Remarkably, the nanoscale order-disorder phase transition occurs at significantly reduced temperatures relative to bulk counterparts, attributed to the presence of twin planes within the PtCu₃ nanowires that effectively lower kinetic barriers for atomic diffusion. This study provides valuable insights into phase transitions in intermetallic nanostructures and establishes a platform for further exploration of their fundamental properties and catalytic applications.</p>

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Nanoscale ordering in PtCu3 nanowires: Low-temperature synthesis and structural characterization of the L12 phase

  • 期刊论文

  • 发表日期：

    2025年9月16日

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  • Debadarshini Samantaray,
  • Suparna Mondal,
  • Anupam Mishra

摘要

Intermetallic compounds (IMCs), distinguished by their ordered atomic arrangements and electronic uniformity, exhibit enhanced physicochemical properties compared to their disordered alloy counterparts. Notably, Pt-based intermetallic alloys, such as PtCu₃, demonstrate exceptional catalytic activity and stability in oxygen reduction reaction (ORR) applications. Conventional methods to induce atomic ordering in random alloy structures typically involve high-temperature annealing, which often leads to particle sintering and diminished catalytic performance. This challenge is further amplified in one-dimensional (1D) nanostructures due to their inherent anisotropic characteristics. Herein, we report a facile wet chemical synthesis approach to produce ultrathin, single-crystalline PtCu₃ alloy nanowires exhibiting the disordered (Fm \(\:\stackrel{-}{3}\) m) phase and the ordered L1₂ phase (Pm \(\:\stackrel{-}{3}\) m) at approximately 180 °C with precise morphological control. Structural characterization via aberration-corrected scanning transmission electron microscopy (STEM) equipped with high-angle annular dark field (HAADF) detector, coupled with X-ray diffraction analysis, confirms the attainment of ordered atomic arrangements. Remarkably, the nanoscale order-disorder phase transition occurs at significantly reduced temperatures relative to bulk counterparts, attributed to the presence of twin planes within the PtCu₃ nanowires that effectively lower kinetic barriers for atomic diffusion. This study provides valuable insights into phase transitions in intermetallic nanostructures and establishes a platform for further exploration of their fundamental properties and catalytic applications.