论文标题
ag $ _x $ pt $ _ {1-x} $纳米粒子的熔融属性
Melting properties of Ag$_x$Pt$_{1-x}$ nanoparticles
论文作者
论文摘要
在纳米级，材料表现出独特的特性，这些特性与散装状态的特性差异很大。对于Ag $ _x $ pt $ _ {1-x} $ nanoalloys，我们的目的是研究不同尺寸和成分的纳米颗粒的固体液体过渡。该系统特别有趣，因为PT具有较高的熔点（2041 K与Ag的1035 K相比），这可以在相对较高的温度下在不同的催化反应期间保持纳米颗粒固体，例如我们在纳米管的生长中需要。我们使用蒙特卡洛代码中在恒定温度和规范合奏中的化学组成中实现的半经验潜能进行了原子量表模拟。我们观察到熔化温度随尺寸（纯系统和合金）和组成而降低。我们表明，融化系统地通过中间阶段，具有结晶芯（纯铂或混合PTAG取决于组合物）和纯银液体皮肤，这强烈质疑在碳纳米管合成的催化反应中具有固定的固体颗粒的想法。
At the nanoscale, materials exhibit unique properties that differ greatly from those of the bulk state. In the case of Ag$_x$Pt$_{1-x}$ nanoalloys, we aimed to study the solid-liquid transition of nanoparticles of different sizes and compositions. This system is particularly interesting since Pt has a high melting point (2041 K compare to 1035 K for Ag) which could keep the nanoparticle solid during different catalytic reactions at relatively high temperatures, such as we need in the growth of nanotubes. We performed atomic scale simulations using semi-empirical potential implemented in a Monte Carlo code at constant temperature and chemical composition in canonical ensemble. We observed that the melting temperature decreases with the size (pure systems and alloys) and the composition. We show that the melting systematically passes through an intermediate stage with a crystalline core (pure platinum or mixed PtAg depending on the composition) and a pure silver liquid skin, which strongly questions the idea of having a faceted solid particle in catalytic reactions for carbon nanotubes synthesis.
