中文摘要：

为研究Pt-Pd合金纳米粒子的稳定结构,进一步了解其催化性能,采用改进粒子群（PSO）算法并分别结合量子修正的Sutton-Chen（QSC）多体势和紧束缚二阶矩阵近似势（TBM）,对具有不同尺寸和不同原子比例的高晶指数二十四面体Pt-Pd合金纳米粒子的结构稳定性进行对比研究.结果表明：QSC和TBM势函数下得到的原子分布趋势一致.当Pt原子比例较小时,两种势函数下的稳定结构都偏向于壳层结构的分布;随着Pt原子比例的增加,TBM势函数下的稳定结构呈类壳层结构分布,而QSC势函数的稳定结构呈核壳分布,其偏聚程度更高.

英文摘要：

In this paper, the improved particle swarm optimization （PSO） algorithm combined with quantum correction Sutton-Chen （QSC） multi-body potential and tight-binding approximation potential second-order matrix （TBM） was employed to investigate the stable structure of Pt-Pd nanoparticles, taking into consideration sizes and l~t compositions. Experiment results reveal that the atomic distribution exhibits the same trend for Pd atoms and Pt atoms. Pd atoms tend to distribute on the surface, while Pt atoms tend to distribute at the inner sites, which is beneficial to lowering the total energy of the structure. Nanoparticles are present in a multi-shell structure for small Pt concentration with both potentials. In addition, the Pt-Pd nanoparticles tend to form a muhi- shell-like structure for the TBM potential with Pt compositions increase. The Pt-Pd nanoparticles segregatie more intensely for the QSC potential is higher than that for the tight-binding potentials, with a core-shell structure.