Real-time imaging and elemental mapping of AgAu nanoparticle transformations
Real-time imaging and elemental mapping of AgAu nanoparticle transformations
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DOI：
10.1039/c4nr04837g
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发表时间：
2014-11-01
期刊：
影响因子：
6.7
通讯作者：
Haigh, S. J.
中科院分区：
文献类型：
--
作者：
Lewis, E. A.;Slater, T. J. A.;Haigh, S. J.
我们报告的控制合金化，氧化，并随后减少个别AgAu纳米粒子在扫描透射电子显微镜（STEM）。通过电子束诱导氧化和原位加热淬火的顺序应用，我们展示了Ag-Au核壳纳米颗粒转变为：AgAu合金，Au-Ag核壳，中空Au-Ag 2 O核壳，和Au-Ag 2 O蛋黄壳纳米颗粒。我们能够直接以原子分辨率实时成像这些形态学转变，并执行能量色散X射线（EDX）光谱成像，以亚纳米分辨率映射不断变化的元素分布。通过结合像差校正STEM成像和高效EDX光谱，我们不仅能够量化氧化过程中Kirkendall空隙的生长和聚结，还能够量化该反应过程中发生的成分变化。这是第一次有可能跟踪经历氧化驱动的壳生长和中空化的单个纳米颗粒中元素的变化分布。
We report the controlled alloying, oxidation, and subsequent reduction of individual AgAu nanoparticles in the scanning transmission electron microscope (STEM). Through sequential application of electron beam induced oxidation and in situ heating and quenching, we demonstrate the transformation of Ag-Au core shell nanoparticles into: AgAu alloyed, Au-Ag core shell, hollow Au-Ag2O core shell, and Au-Ag2O yolk-shell nanoparticles. We are able to directly image these morphological transformations in real-time at atomic resolution and perform energy dispersive X-ray (EDX) spectrum imaging to map changing elemental distributions with sub-nanometre resolution. By combining aberration corrected STEM imaging and high efficiency EDX spectroscopy we are able to quantify not only the growth and coalescence of Kirkendall voids during oxidation but also the compositional changes occurring during this reaction. This is the first time that it has been possible to track the changing distribution of elements in an individual nanoparticle undergoing oxidation driven shell growth and hollowing.