Improving electron tomography of mesoporous silica by Ga intrusion

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. • Ga intrusion boosts HAADF signal by 5x in mesoporous silica • ET resolution improves from 3.5 nm to 2.3 nm in 3D reconstructions • Enhanced contrast enables precise segmentation and structure analysis • Charging during FIB milling is mitigated by increased conductivity • Approach is extendable to other porous light-element beam-sensitive materials