论文标题
对双金属PDPT纳米颗粒在有限温度下的稳定性的第一原理研究
First-principles study of the stability of bimetallic PdPt nanoparticles under a finite temperature
论文作者
论文摘要
为了了解核壳和固定双金属纳米颗粒的稳定性的振动和构型熵效应，我们从理论上研究了PDPT纳米颗粒的过量能量，采用了（PDPT）201的模型。使用密度函数方法2 nm。振动能和熵项有助于核壳和固定纳米颗粒的总能量。配置熵项仅针对固体纳米颗粒定义。尽管振动能和熵项的绝对值远大于配置熵项的绝对值，但由于不同的原子构型之间的差异很小，它们的贡献受到过量自由能的形式受到限制。从我们的第一原理计算中可以清楚地确认配置熵项对多余的自由能的巨大贡献。为了估计基于多余能量的核壳和固定金属纳米颗粒的稳定性，构型熵项是主要因素。
To understand the vibrational and configurational entropy effects for the stability of core-shell and solid-solution bimetallic nanoparticles, we theoretically investigated the excess energy of PdPt nanoparticles, adopting the (PdPt)201 model of ca. 2 nm by using the density functional method. The vibrational energy and entropy terms contributed to the total energy of both core-shell and solid-solution nanoparticles. The configurational entropy term was defined only for the solid-solution nanoparticles. Although the absolute values of vibrational energy and entropy terms were much larger than that of configurational entropy term, their contributions were limited in the form of excess free energy due to the small difference between different atomic configurations. The large contribution of configurational entropy term to the excess free energy was clearly confirmed from our first-principles calculations. To estimate the stability of core-shell and solid-solution metal nanoparticles based on the excess energy, the configurational entropy term was the dominant factor.
