Visualization of hierarchically structured zeolite bodies from macro to nano length scales

Abstract

A major challenge in the implementation of laboratory-designed catalysts is the scale-up into technically relevant forms. Advanced characterization is essential to understand and optimize catalyst assembly and function in industrial reactors. This Article presents an integrated approach to visualizing millimetre-sized extrudates and granules of a hierarchical MFI-type zeolite, displaying trimodal networks of micropores (0.56 nm), intracrystalline mesopores (∼10 nm) and macropores (∼200-300 nm). As exemplified for the conversion of methanol to olefins, the hierarchical zeolite yields a superior performance compared to its conventional analogue. The combination of dedicated specimen preparation with state-of-the-art optical, X-ray and electron-based microscopic and tomographic techniques proves a powerful methodology to reveal otherwise inaccessible information regarding structural organization over the whole range of length scales. It is expected that these tools will play a crucial role in the rationalization of scale-up principles in catalyst development.

Trimodally porous SnO2 nanospheres with three-dimensional interconnectivity and size tunability: a one-pot synthetic route and potential application as an extremely sensitive ethanol detector

“…21,44 In addition, controlling the macropores, mesopores and micropores is extremely important for increasing or optimizing the accessibility of gases and ions to the surfaces of a material. From this perspective, the realization and tuning of multimodal pores with a high level of control over their size, distribution, volume and interconnectivity in the present study could provide a general solution for improving the performance of many energy and environmental applications, such as Li-ion batteries, 45 supercapacitors, 46 catalysts 47,48 and gas sensors.…”

Visualizing MOF Mixed Matrix Membranes at the Nanoscale: Towards Structure‐Performance Relationships in CO2/CH4 Separation Over NH2‐MIL‐53(Al)@PI

“…[ 21 ] The Ga + primary focused ion beam is used to controllably sputter a selected area of the specimen, precisely removing thin slices of material and enabling a series of consecutive cross-sections to be studied individually. After alignment of the stack of SEM images, the internal structure of the analyzed volume can be reconstructed in 3D.…”

Mesopore quality determines the lifetime of hierarchically structured zeolite catalysts

“…One of the foremost challenges in addressing this most overlooked aspect is the identification of samples with comparable absolute porosity and acidity, but distinct mesopore topology. Furthermore, advanced space-and time-resolved characterization tools are essential to access, localize and quantify nanostructural details of the hierarchical arrangement 13,14 .…”