Electron tomography (ET) has rapidly developed into a powerful technique to characterize the three-dimensional (3D) structure of complex materials, with nanometer resolution, for a wide range of applications including heterogeneous catalysis. In these 3D studies, scanning transmission electron microscopy (STEM) has been the most widely used imaging mode, due to both its incoherent nature, which avoids the appearance of diffraction-related artefacts, and its sensitivity to composition, an important question for most catalytic systems. Though initially used as a qualitative tool to visualize 3D nanostructures, more recently STEM tomography is being also exploited to retrieve quantitative information in 3D. In this article, we review recent developments of STEM-based tomography for the understanding of heterogeneous catalysts at the nanometer level. The new possibilities opened by quantitative analysis will be illustrated by selected cases in which different parameters are calculated from 3D reconstructions and compared to their macroscopic measurements. The key influence of the latest developments in reconstruction and segmentation methods to assess reliability and accuracy in the quantification process is highlighted.

电子断层扫描（ET）已迅速发展成为一种功能强大的技术，可表征具有纳米级分辨率的复杂材料的三维（3D）结构，适用于包括多相催化在内的广泛应用。在这些3D研究中，扫描透射电子显微镜（STEM）由于其不相干的性质（避免了与衍射有关的伪像的出现）及其对成分的敏感性而成为最广泛使用的成像模式，这是大多数催化方法的重要问题系统。尽管最初用作可视化3D纳米结构的定性工具，但最近，STEM层析成像也被用于检索3D定量信息。在本文中，我们回顾了基于STEM层析成像的最新进展，以了解纳米级的非均相催化剂。定量分析带来的新可能性将通过选定的案例加以说明，其中从3D重建中计算出不同的参数并将其与宏观测量结果进行比较。强调了重建和分割方法的最新发展对评估量化过程中的可靠性和准确性的关键影响。