Imaging study electron tomography

First-of-its kind results [14,15] with electron tomography for the study of zeolites have been obtained with Ag/Na-Y. The location of the Ag particles of about 10 nm could be unequivocally established with respect to the surface and the interior of the crystals. The moderate resolution of 5 nm of the reconstructed images in this study related to the rather large zeolite crystals (500 nm) involved. Hereafter, we first discuss in more detail the use of electron tomography to study mesopores in zeolite crystals and, secondly, case studies involving metal particles and pore architecture of ordered mesoporous materials. 

Electron tomography (ET) can now be applied on a routine basis using an automated electron microscope in combination with image processing and visualization software. Three-dimensional information with nanometer resolution has been obtained for structural studies of molecular sieves. 

Tunable VUV and soft X-rays from synchrotron light sources are ideally suited to study surface, near surface (thin film) and interface phenomena. These photons can access many useful core levels of many elements (site specific), they usually do not penetrate very deep and they produce electrons with very short escape depths (surface sensitivity). On the other hand, hard X-rays with great penetration power are ideally suited for all kinds of imaging, such as tomography of rocks and soils. 

More recently, electron microscopy and tomography studies have been applied as well for visualization of microstructures formed by agglomerated carbon and Pt particles (Thiele et al., 2013). The resolution of imaging and tomographical techniques has seen tremendous progress. FIB-SEM can be employed to obtain cross-sectional images, which can be used to reconstruct the 3D structure of CLs. 

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