Intergrowth Structure of Zeolite Crystals as Determined by Optical and Fluorescence Microscopy of the Template‐Removal Process

π–π interaction of aromatic groups in amphiphilic molecules directing for single-crystalline mesostructured zeolite nanosheets

“…During this process, the crystals almost retained their initial size. As mentioned above, compared with the spontaneous crystallization growth of zeolitic nanosheets by small SDAs 33,34 , our strategy and the obtained products based on the self-assembly of amphiphilic molecules demonstrated the difference resulting from as well as the advantage of available control on uniform mesoscopic porosity, crystallographic correlation between two perpendicular crystals depending on the molecular size, the in situ transformation mechanism and structural stability.…”

“…It is well known that rotational boundaries are commonly found in MFI zeolite with an overgrown relationship between the (h00) and (0k0) faces 32,33 , which increases the possibility of the construction of a hierarchical structure with a large surface area and pore volume. The approximate cell parameters of a and b in MFI and the similar 10-ring pores provide a fundamental possibility for the occurrence of the phenomena of intergrowth on itself, which is inherent to the MFI structure.…”

Visualizing the Crystal Structure and Locating the Catalytic Activity of Micro‐ and Mesoporous ZSM‐5 Zeolite Crystals by Using In Situ Optical and Fluorescence Microscopy

“…[24] Reconstruction of the intergrowth structure of the ZSM-5 crystals by in situ confocal fluorescence microscopy: Zeolitic materials, such as SAPO-5, SAPO-34, and ZSM-5, are not single-crystalline and comprise distinct subunits, evidencing a complex intergrowth structure. [25,28] As the pore geometries in the different building blocks within each of these structures are not always identical, this phenomenon has a large effect on the accessibility of the pores in different regions of the crystals, which may, therefore, significantly affect the catalytic activity. To investigate the intergrowth structure of the micro-and mesoporous ZSM-5 crystals under study, the as-synthesized crystals were calcined at 773 K for 1 h, cooled to room temperature, and confocal fluorescence images were taken.…”

“…Recently, the intergrowth structure of similar, though larger, ZSM-5 crystals was revealed in this manner. [25] Figure 2 shows confocal fluorescence images of the microporous ZSM-5 crystals taken after cooling, which reveal the location of the fluorescent species originating from the template removal phenomena. Firstly, from the confocal topview image (Figure 2 a) intense fluorescence is observed in the middle part of the crystal, indicative of more fluorescent species being present in this region than in the outer parts, and suggesting that the different parts are not interconnected.…”

“…To examine the intergrowth structure of these zeolite materials, confocal fluorescence microscopy was employed, based on the mapping of the template removal process in individual crystals. [25] The effect of mesoporosity on the shape selectivity and catalytic activity was studied by the oligomerization of different styrene compounds. [26,27] Furthermore, optical microspectroscopic examination by using polarized light revealed the microscopic alignment of styrene product molecules in the micropores of the zeolite crystals and, hence, the pore orientation.…”