利用原子分辨率低角度环形暗场扫描透射电子显微镜对二氧化铈进行氧化态敏感成像。
Oxidation-state sensitive imaging of cerium dioxide by atomic-resolution low-angle annular dark field scanning transmission electron microscopy.
作者信息
Johnston-Peck Aaron C, Winterstein Jonathan P, Roberts Alan D, DuChene Joseph S, Qian Kun, Sweeny Brendan C, Wei Wei David, Sharma Renu, Stach Eric A, Herzing Andrew A
机构信息
Materials Measurement Lab, National Institute of Standards Technology, Gaithersburg, MD 20899, USA.
Center for Nanoscale Science and Technology, National Institute of Standards Technology, Gaithersburg, MD 20899, USA.
出版信息
Ultramicroscopy. 2016 Mar;162:52-60. doi: 10.1016/j.ultramic.2015.12.004. Epub 2015 Dec 17.
Low-angle annular dark field (LAADF) scanning transmission electron microscopy (STEM) imaging is presented as a method that is sensitive to the oxidation state of cerium ions in CeO2 nanoparticles. This relationship was validated through electron energy loss spectroscopy (EELS), in situ measurements, as well as multislice image simulations. Static displacements caused by the increased ionic radius of Ce(3+) influence the electron channeling process and increase electron scattering to low angles while reducing scatter to high angles. This process manifests itself by reducing the high-angle annular dark field (HAADF) signal intensity while increasing the LAADF signal intensity in close proximity to Ce(3+) ions. This technique can supplement STEM-EELS and in so doing, relax the experimental challenges associated with acquiring oxidation state information at high spatial resolutions.
低角度环形暗场（LAADF）扫描透射电子显微镜（STEM）成像被作为一种对CeO2纳米颗粒中铈离子氧化态敏感的方法提出。这种关系通过电子能量损失谱（EELS）、原位测量以及多层图像模拟得到了验证。Ce(3+)离子半径增加引起的静态位移影响电子通道过程，增加低角度的电子散射，同时减少高角度的散射。这个过程表现为在靠近Ce(3+)离子处降低高角度环形暗场（HAADF）信号强度，同时增加LAADF信号强度。该技术可以补充STEM-EELS，从而缓解在高空间分辨率下获取氧化态信息所面临的实验挑战。
Zotero 插件