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首页> 外文期刊>RSC Advances >Exposure of mass-selected bimetallic Pt-Ti nanoalloys to oxygen explored using scanning transmission electron microscopy and density functional theory
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Exposure of mass-selected bimetallic Pt-Ti nanoalloys to oxygen explored using scanning transmission electron microscopy and density functional theory

机译：使用扫描透射电子显微镜和密度泛函理论探索质量选择的双金属PT-TI纳米铝氧化物对氧气的影响

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摘要

The response of nanoparticles to exposure to ambient conditions and especially oxidation is fundamental to the application of nanotechnology. Bimetallic platinum-titanium nanoparticles of selected mass, 30 kDa and 90 kDa, were produced using a magnetron sputtering gas condensation cluster source and deposited onto amorphous carbon TEM grids. The nanoparticles were analysed with a C-s-corrected Scanning Transmission Electron Microscope (STEM) in High Angle Annular Dark Field (HAADF) mode. It was observed that prior to full Ti oxidation, Pt atoms were dispersed within a Ti shell. However, after full oxidation by prolonged exposure to ambient conditions prior to STEM, the smaller size 30 kDa particles form a single Pt core and the larger size 90 kDa particles exhibit a multi-core structure. Electron beam annealing induced a single core morphology in the larger particles. First principles density functional theory (DFT) calculations were employed to calculate the lowest energy structure of the Pt-Ti nanoparticles with and without the presence of oxygen. It was demonstrated that, as the concentration of oxygen increases, the lowest energy structure changes from dispersed Pt to multiple Pt cores and finally a single Pt core, which is in good agreement with the experimental observations.
机译：纳米颗粒暴露于环境条件，尤其是氧化的响应是纳米技术应用的基础。使用磁控溅射气体缩合簇源并沉积在无定形碳TEM网格上，制备选定质量，30kDa和90kDa的双金属铂 - 钛纳米粒子。用高角度环形暗场（HAADF）模式用C-S校正的扫描透射电子显微镜（阀杆）分析纳米颗粒。观察到，在完全Ti氧化之前，Pt原子分散在Ti壳内。然而，在茎之前通过延长暴露于环境条件的完全氧化之后，较小的30kDa颗粒形成单个Pt核，较大尺寸90kDa颗粒表现出多核结构。电子束退火在较大颗粒中诱导单核形态。第一个原理的密度函数理论（DFT）计算用于计算具有氧气的PT-Ti纳米粒子的最低能量结构。结果证明，随着氧气浓度的增加，最低能量结构从分散的Pt变为多个Pt核，最后是单个Pt核心，这与实验观察良好。

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  • 来源
    《RSC Advances》 |2018年第48期|共7页
  • 作者

    Gholhaki Saeed; Hung Shih-Hsuan; Cant David J. H.; Blackmore Caroline E.; Shard Alex G.; Guo Quanmin; McKenna Keith P.; Palmer Richard E.;

  • 作者单位

    Univ Birmingham Sch Phys &

    Astron Birmingham B15 2TT W Midlands England;

    Univ York Dept Phys York YO10 5DD N Yorkshire England;

    Natl Phys Lab Hampton Rd Teddington TW11 0LW Middx England;

    Univ Birmingham Sch Phys &

    Astron Birmingham B15 2TT W Midlands England;

    Natl Phys Lab Hampton Rd Teddington TW11 0LW Middx England;

    Univ Birmingham Sch Phys &

    Astron Birmingham B15 2TT W Midlands England;

    Univ York Dept Phys York YO10 5DD N Yorkshire England;

    Swansea Univ Coll Engn Bay Campus Fabian Way Swansea SA1 8EN W Glam Wales;

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  • 正文语种 eng
  • 中图分类 化学;
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