论文标题
氧吸附和氧化对PD纳米晶体应变状态的影响
Effect of oxygen adsorption and oxidation on the strain state of Pd nanocrystals
论文作者
论文摘要
X射线粉末衍射使用同步加速器光源揭示了氧化后钯纳米接管中形态和应变状态的显着修饰。通过氧化纳米颗粒的静态分量测量的短距离应变较高。而与衍射峰的线扩展有关的远距离应变却降低了。使用经典分子动力学和密度功能理论的多尺度建模，我们将远程应变的减小连接到氧化纳米摄管剂的截断的增加，而较高的短距离应变被证明是由于氧气吸附而表面软化所致。不同晶体学方面的不同表面障碍导致截短纳米颗粒不同表面上的氧气激活的相反趋势。
X-ray powder diffraction using a synchrotron light source reveals significant modifications to both morphology and strain state in Palladium nanocubes after oxidation. Short-range strain measured by the static component of the Debye-Waller coefficient is observed to be higher in the oxidized nanoparticles; while long-range strain related to the line broadening of the diffraction peaks is seen to decrease. Using multiscale modelling with classical molecular dynamics and density functional theory, we connect the decrease in long-range strain to the increased truncation of the oxidized nanocubes, while the higher short-range strain is shown to be due to surface softening from oxygen adsorption. Different surface disorder on different crystallographic facets lead to opposing trends for oxygen activation on the different exposed surfaces of the truncated nanoparticles.
