Wen Yu-Hua, Huang Rao, Shao Gui-Fang, Sun Shi-Gang
Collaborative Innovation Center for Optoelectronic Semiconductors and Efficient Devices, Department of Physics, Xiamen University , Xiamen 361005, China.
Department of Automation, Xiamen University , Xiamen 361005, China.
J Phys Chem Lett. 2017 Sep 7;8(17):4273-4278. doi: 10.1021/acs.jpclett.7b01880. Epub 2017 Aug 28.
Co-Pt and Co-Au core-shell nanoparticles were heated by molecular dynamics simulations to investigate their thermal stability. Two core structures, that is, hcp Co and fcc Co, have been addressed. The results demonstrate that the hcp-fcc phase transition happens in the hcp-Co-core/fcc-Pt-shell nanoparticle, while it is absent in the hcp-Co-core/fcc-Au-shell one. The stacking faults appear in both Pt and Au shells despite different structures of the Co core. The Co core and Pt shell concurrently melt and present an identical melting point in both Co-Pt core-shell nanoparticles. However, typical two-stage melting occurs in both Co-Au core-shell nanoparticles. Furthermore, the Au shell in the hcp-Co-core/fcc-Au-shell nanoparticle exhibits a lower melting point than that in the fcc-Co-core/fcc-Au-shell one, while the melting points are closely equal for both hcp and fcc Co cores. All of these observations suggest that their thermal stability strongly depends on the structure of the core and the element of the shell.
通过分子动力学模拟对钴 - 铂和钴 - 金核壳纳米颗粒进行加热，以研究它们的热稳定性。研究了两种核心结构，即六方钴（hcp Co）和面心立方钴（fcc Co）。结果表明，在六方钴核/面心立方铂壳纳米颗粒中发生了六方 - 面心立方相变，而在六方钴核/面心立方金壳纳米颗粒中未出现这种相变。尽管钴核结构不同，但在铂壳和金壳中均出现了堆垛层错。在两种钴 - 铂核壳纳米颗粒中，钴核和铂壳同时熔化并呈现相同的熔点。然而，在两种钴 - 金核壳纳米颗粒中均出现了典型的两阶段熔化现象。此外，六方钴核/面心立方金壳纳米颗粒中的金壳熔点低于面心立方钴核/面心立方金壳纳米颗粒中的金壳熔点，而六方钴核和面心立方钴核的熔点相近。所有这些观察结果表明，它们的热稳定性强烈依赖于核心结构和壳层元素。
