Mechanochemically assisted hydrothermal synthesis of Sn-substituted MFI-type silicates |
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Authors: | Kiyoshi Kanie Moe Sakaguchi Fumiya Muto Mami Horie Masafumi Nakaya Toshiyuki Yokoi |
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Affiliation: | 1. Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Japan;2. Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan;3. JST-PREST, Tokyo, Japan |
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Abstract: | Substitution of Al atoms in a zeolite framework by catalytic metal atoms has attracted considerable attention because the catalytic behavior can be tuned by the substituted atoms. In the present study, Sn-substituted MFI-type silicates were synthesized using a hydrothermal reaction of an amorphous Si-O-Sn precursor prepared by mechanochemical grinding of SiO2 and Sn(OH)4. The mechanochemical treatment was found to be a key technique for obtaining the amorphous Si-O-Sn precursor, where tetrahedral Sn4+ species were incorporated into the amorphous matrix. The Sn content in the framework of the MFI-type silicates was successfully controlled by the initial HCl/Si molar ratio of the hydrothermal procedures. Optical reflectance measurements revealed that the Sn4+ ions were dispersedly incorporated into the silicate framework while preserving the initial tetrahedrally coordinated species. Infrared results imply that the resulting Sn-substituted MFI-type silicate has Brønsted acid character. Precise control of the Brønsted and Lewis acid properties by Sn doping is a promising approach to the development of novel types of zeolite-based catalytic materials. |
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Keywords: | Mechanochemical zeolite hydrothermal silicate MFI |
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