Improving electron tomography of mesoporous silica by Ga intrusion

TL;DR

This paper presents a gallium intrusion method that significantly enhances electron tomography imaging of mesoporous silica, improving contrast, resolution, and analysis capabilities for light-element materials.

Contribution

Introduction of a Ga intrusion technique that boosts contrast and resolution in electron tomography of mesoporous silica, enabling detailed 3D characterization of porous structures.

Findings

HAADF STEM signal increased by 5 times

Reconstruction resolution improved by 34%

Interface sharpness enhanced by 49%

Abstract

Electron tomography (ET) offers nanoscale 3D characterization of mesoporous materials but is often limited by their low scattering contrast. Here, we introduce a gallium (Ga) intrusion strategy for mesoporous silica that dramatically improves imaging contrast - a key benefit that enables more accurate 3D reconstructions. By infiltrating Ga through a modified mercury intrusion porosimetry process, the high-angle annular dark-field (HAADF) STEM signal is enhanced by 5 times, resulting in a 34% improvement in reconstruction resolution and a 49% enhancement in interface sharpness. In addition, the increased sample conductivity facilitates focused ion beam (FIB) milling by minimizing charging effects and reducing drift. This approach enables precise segmentation and quantitative analysis of pore connectivity and size distribution, thereby extending the applicability of ET to light-element non-conductive materials and advancing structure-property characterization of complex porous systems.