From Microporous to Mesoporous Molecular Sieve Materials and Their Use in Catalysis

Multimodal Zr-Silicalite-1 zeolite nanocrystal aggregates with interconnected hierarchically micro-meso-macroporous architecture and enhanced mass transport property

“…2). Generally, under the effect of structure directing agent, the MFI-type zeolite nanocrystals were easily formed by the conventional hydrothermal condition [3]. However, this rapid growth and the strong interaction between the growing zeolite Zr-Silicalite-1 nanocrystals during the crystallization process would lead to the collapse of the macropores constructed from the aggregation of nanoparticles in the hydrothermal condition.…”

“…3a), which indicated the presence of immense amounts of amorphous zirconosilicate or oxides in the framework of the precursor. After crystallization transformation process for 2 days at 130°C, the resonance at À92 ppm (Q 2 ) disappeared, and a highly intense resonance at À112 ppm [Q 4 , Si(OSi) 4 ] and a shoulder peak at À102 ppm [Q 3 , Si(OSi) 3 (OH) or Si(OSi) 3 (OZr)] were observed (Fig. 3b), indicating that the coordination states of the Si and Zr species were transformed from an amorphous to a crystalline framework and micro-meso-macroporous product consists primarily of cross-linked Q 4 silica units and Q 3 units as deduced from a very high Q 4 /Q 3 ratio.…”

“…MFI-type zeolite is one of crystalline microporous catalysts and is widely used in various hydrocarbon processing (such as ZSM-5) and oxidation catalysis (such as TS-1) owing to their strong catalytic performance, excellent thermal, hydrothermal and chemical stabilities [1][2][3][4][5][6][7]. However, one disadvantage of these zeolitic catalysts is that their pores (about 0.55 nm) are too small to be accessed by bulky reactants hindering their use in the fine chemical and petroleum processing industries [8,9].…”

Competitive Adsorption of Substrate and Solvent in Sn‐Beta Zeolite During Sugar Isomerization

“…Still, the activity of Sn‐Beta in sugar isomerization is low compared with enzymes. Although it is well known that slow diffusion in zeolitic micropores can limit the reaction rate,17, 18, 19, 20, 21, 22, 23, 24 such effects have not been reported for Sn‐Beta‐catalyzed isomerization of sugars 25…”

Hierarchically structured meso-macroporous aluminosilicates with high tetrahedral aluminium content in acid catalysed esterification of fatty acids

“…Recent studies highlight the promising superiority of hierarchical meso-macrostructured materials in large series of catalytic reactions [1][2][3][4][5][6][7][8][9][10][11], thanks to improved diffusion and mass transfer properties as well as limitation of poisoning and coking, especially when large molecules are used and reactions are performed in viscous liquid phase [12,13]. A large panel of original strategies, often quite tedious to achieve, have been developed to allow the incorporation of desirable porosities at different length scales into one single body.…”