One-pot synthesis of silanol-free nanosized MFI zeolite

• Published in: Nature materials Vol. 16; no. 10; pp. 1010 - 1015
• Main Authors: Grand, Julien, Talapaneni, Siddulu Naidu, Vicente, Aurélie, Fernandez, Christian, Dib, Eddy, Aleksandrov, Hristiyan A., Vayssilov, Georgi N., Retoux, Richard, Boullay, Philippe, Gilson, Jean-Pierre, Valtchev, Valentin, Mintova, Svetlana
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01-10-2017; Nature Publishing Group
• Subjects: 140/131; 140/133; 639/301/299/1013; 639/925/357; Acidity; Biomaterials; Carbon dioxide; Catalysis; Chemical Sciences; Chemical synthesis; Condensed Matter Physics; Crystals; Epoxidation; Hydrophobicity; Materials Science; Minerals; Nanomaterials; Nanostructure; Nanotechnology; Nitrogen dioxide; Optical and Electronic Materials; Separation; Silica; Silicon dioxide; Styrene; Tungsten; Zeolites; Nanoscale materials; Porous materials
• ISSN: 1476-1122; 1476-4660
• DOI: 10.1038/nmat4941

The synthesis of nanostructured zeolites enables modification of catalytically relevant properties such as effective surface area and diffusion path length. Nanostructured zeolites may be synthesized either in alkaline media, and so contain significant numbers of hydrophilic silanol groups, or in expensive and harmful fluoride-containing media. Here, we report and characterize, using a combination of experimental and theoretical techniques, the one-pot synthesis of silanol-free nanosized MFI-type zeolites by introducing atomically dispersed tungsten; this prevents silanol group occurrence by forming flexible W–O–Si bridges. These W–O–Si bonds are more stable than Si–O–Si in the all-silica MFI zeolite. Tungsten incorporation in nanosized MFI crystals also modifies other properties such as structural features, hydrophobicity and Lewis acidity. The effect of these is illustrated on the catalytic epoxidation of styrene and separation of CO
2
and NO
2
. Silanol-free nanosized W-MFI zeolites open new perspectives for catalytic and separation applications.
Nanostructured zeolites were synthesized without hydrophilic silanol groups, and without fluoridation, via the introduction of atomically dispersed tungsten. This resulted in improved catalytic and gas separation properties.