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.

中文翻译：

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准四维透射电镜下与空间位置相关的负载纳米粒子的烧结行为

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关键问题。然而，将原位刺激和三维（3D）表征相结合的挑战阻碍了对烧结行为的深刻理解，因此空间位置对纳米粒子烧结的影响长期以来一直被忽视。在此，基于集成原位焦耳加热和电子断层扫描的自制支架，开发了准四维 (4D) 透射电子显微镜表征方法，以揭示负载纳米粒子的空间位置及其对尺寸分布和烧结的显着影响行为。3D 可视化和统计分析的结果表明，负载纳米粒子具有很强的位置依赖性烧结行为，其中外部纳米粒子通过迁移聚结进行烧结，而内部纳米粒子通过奥斯特瓦尔德熟化进行烧结。在这项工作中开发的准4D方法也可以扩展到研究其他纳米材料在外部刺激下的3D构型演化。