Center for X-mechanics, Zhejiang University, Hangzhou 310027, China.
ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou, 310027, China.
Nano Lett. 2022 Aug 24;22(16):6523-6529. doi: 10.1021/acs.nanolett.2c01538. Epub 2022 Aug 4.
The performance degradation via sintering phenomenon is a critical issue for the application of supported nanoparticles in industrial catalysis. However, the challenges to combine in situ stimulation and three-dimensional (3D) characterization hinder a profound understanding of sintering behaviors, thus the effect of spatial location on nanoparticles sintering has long been neglected. Herein, based on a homemade holder integrated with in situ Joule heating and electron tomography, a quasi-four-dimensional (4D) transmission electron microscope characterization approach is developed to reveal the spatial location of supported nanoparticles and its pronounced impact on size distribution and sintering behaviors. The results of 3D visualization and statistical analysis demonstrate a strong location-dependent sintering behavior of supported nanoparticles, where external nanoparticles sinter via migration coalescence, and internal nanoparticles sinter via Ostwald ripening. The quasi-4D methods developed in this work can also be extended to the study on 3D configuration evolution of other nanomaterials under an external stimulus.
通过烧结现象导致的性能下降是负载型纳米粒子在工业催化中应用的一个关键问题。然而，原位激发和三维（3D）表征相结合的挑战阻碍了对烧结行为的深入理解，因此，纳米粒子烧结的空间位置长期以来被忽视。在此，基于一个集成了原位焦耳加热和电子断层扫描的自制夹具，开发了一种准四维（4D）透射电子显微镜表征方法，以揭示负载型纳米粒子的空间位置及其对尺寸分布和烧结行为的显著影响。3D 可视化和统计分析的结果表明，负载型纳米粒子具有强烈的位置依赖性烧结行为，其中外部纳米粒子通过迁移聚结烧结，而内部纳米粒子通过奥斯特瓦尔德熟化烧结。本工作中开发的准 4D 方法也可扩展到研究在外部刺激下其他纳米材料的 3D 构型演变。
