Intergrowth Structure of Zeolite Crystals and Pore Orientation of Individual Subunits Revealed by Electron Backscatter Diffraction/Focused Ion Beam Experiments

Stavitski, Eli; Drury, M. R.; Winter, D. A. Matthijs de; Kox, Marianne H. F.; Weckhuysen, Bert M.

doi:10.1002/anie.200801433

Cited by 81 publications

(35 citation statements)

References 35 publications

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“…Further experimental evidence for this intergrowth structure could be obtained using a combination of electron back-scatter diffraction (EBSD) and focused ionbeam (FIB) milling experiments. [53] As the oligomerization reaction is likely to occur within the zeolite channels, the carbocations would be expected to be entrapped and aligned within the pores. Such an alignment may be revealed using optical absorption measurements with polarized light, as the photoactive molecules absorb light polarized parallel to their dipole moment vector.…”

Section: Pore Alignment Shape Selectivity and Reactivity Patterns Wmentioning

confidence: 99%

Chemical Imaging of Spatial Heterogeneities in Catalytic Solids at Different Length and Time Scales

2009

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Knowledge of spatiotemporal gradients in heterogeneous catalysts is of paramount importance for the rational design of new and more sustainable catalytic processes. Heterogeneities resulting in space- and time-dependent phenomena occur at different length scales; that is, at the level of catalytic reactors (mm to m), catalyst bodies (microm to mm), catalyst grains (nm to microm), and active sites and metal (oxide) particles (A to nm). This Review documents the recent advances in the development of space- and time-resolved spectroscopic methods for imaging spatial heterogeneities within catalytic processes at these four length scales. Particular emphasis will be on the use of magnetic resonance, optical, and synchrotron-based methods, their capabilities in providing spatial resolution (1D and 2D imaging) and depth profiling (3D imaging) as well as on their time-resolved application, potential for single-molecule and nanoparticle detection, and use under reaction conditions. The Review ends with future prospects on spectroscopic markers for catalytic activity, label-free spectroscopy, tomography at the nanoscale, and correlative microscopic approaches.

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Section: Pore Alignment Shape Selectivity and Reactivity Patterns Wmentioning

confidence: 99%

Chemical Imaging of Spatial Heterogeneities in Catalytic Solids at Different Length and Time Scales

2009

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“…More specifically, the interior of the straight channels (open to the surface in the orange regions of the crystal in Figure 1 a; area A) seem to be much more resistant towards dealumination than the sinusoidal channels (light blue regions in Figure 1 a) exposed to the crystals exterior in region C. [25,31] Remarkably, region B, being the area with straight channels sheltered in the parent ZSM-5 by the 908 rotational barrier (Figure 1 a) is not only the part of the crystal that presents the highest number of mesopores, but also contains the most heterogeneous mesopore size distribution as compared to the other crystal regions.…”

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confidence: 99%

Architecture‐Dependent Distribution of Mesopores in Steamed Zeolite Crystals as Visualized by FIB‐SEM Tomography

et al. 2011

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“…[14] Regardless of this trace impurity in CA-FZSM-5, the Al source did not affect the crystal structureb ecauseb oth samples showed typical XRD patterns of an MFI structure. [12] Moreover, DS-HZSM-5 had ah igher 27 Al adsorption intensitya t 55 ppm than CA-FZSM-5 (5.5 10 -7 vs. 3 10 -7 ), indicating the higherc oncentration of framework Al atoms and Brønsted acidic sites. These Al atoms were responsible for the strongB rønsted acidic sites through ac hargeb alance with protons.…”

Section: Resultsmentioning

confidence: 91%

“…After crystallization, as phere-shaped DS-HZSM-5f ormed by oriented sheet-like crystals ( Figure 1a,b) was fabricated. [12] In additiont ot he abundant inter-macropores of 100-200 nm between the crystals (highlighted by ay ellow dashed circle in Figure 1g), some bright spots with as ize of 20-55 nm were observed in the HRTEM image (Figure 1h), indicating the presence of intramesopores. This hollow sphere with at hin zeolite sheet in the shell may im-prove the mass transfer of the reactants and products and lower the pressure drop in af ixed-bed reactor.…”

Section: Resultsmentioning

confidence: 94%

Morphology‐Controlled Synthesis of H‐type MFI Zeolites with Unique Stacked Structures through a One‐Pot Solvent‐Free Strategy

Chen

et al. 2019

ChemSusChem

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H‐type aluminosilicate zeolites are extensively used as solid‐acid catalysts and support materials in industrial catalysis. However, the conventional synthesis methods involving hydrothermal syntheses and ion‐exchange processes suffer from severe water pollution and toxic gas emissions. Herein, H‐type MFI zeolite catalysts with a unique stacked structure were directly synthesized in the presence of NH4F and with the help of zeolite confinement through a solvent‐free route without further ion‐exchange procedures. A range of ex situ and in situ characterization procedures were used to provide evidence of the simultaneous use of pre‐made ZSM‐5 and NH4F as a confined Al source and mineralizer, respectively. The confined zeolite framework of ZSM‐5 prevented the formation of AlFx species between NH4F and Al atoms, ensuring that the prepared samples had desirable acidic properties. Moreover, the resulting morphology could be controlled by using different silica substrates. The obtained H‐type MFI zeolites showed excellent catalytic performance in methanol‐to‐gasoline reactions owing to their unique structure and directly exposed acidic sites. The developed one‐pot strategy provides an alternative method for the facile synthesis of H‐type zeolites with defined morphology.

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Intergrowth Structure of Zeolite Crystals and Pore Orientation of Individual Subunits Revealed by Electron Backscatter Diffraction/Focused Ion Beam Experiments

Cited by 81 publications

References 35 publications

Chemical Imaging of Spatial Heterogeneities in Catalytic Solids at Different Length and Time Scales

Chemical Imaging of Spatial Heterogeneities in Catalytic Solids at Different Length and Time Scales

Architecture‐Dependent Distribution of Mesopores in Steamed Zeolite Crystals as Visualized by FIB‐SEM Tomography

Morphology‐Controlled Synthesis of H‐type MFI Zeolites with Unique Stacked Structures through a One‐Pot Solvent‐Free Strategy

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