Résumé
Herein, we present novel phenylene- and xylylene-bridged silica and metallosilicate materials prepared by non-hydrolytic sol-gel. The hybrid silica are highly porous, chemically similar to periodic mesoporous organosilica (PMO), but amorphous without any pore ordering. Analogous hybrid metallosilicates are obtained by directly incorporating Al, Nb, or Sn in the hybrid silica framework. Exhibiting open texture, surface acidity and tunable hydrophobicity, these materials are excellent candidates for catalytic alcohol dehydration reactions. The gas-phase hydrothermal and thermal stability of these materials is examined. While the hybrid silica is expectedly stable, a stark decrease in stability is observed for phenylene bridged silsesquioxanes upon metal introduction. The extent of the hydrolytic Si–C(sp2) bond cleavage is quantitatively followed by 29Si MAS NMR, TG analysis, and GC-FID analysis of effluent coming from samples exposed to water vapor. Two important features affecting the hydrothermal and thermal stability are identified: (i) the homogeneity of metal dispersion within the silica matrix, and (ii) the electronegativity of the incorporated metal. The stability of hybrid metallosilicates is significantly improved by replacing the phenylene bridges with xylylene bridges, due to the presence of more stable Si–C(sp3) bonds. Interestingly, the latter hybrid metallosilicate proves to be an active catalyst for the dehydration of ethanol to ethylene. Unlike the other hybrid materials presented here, it reaches high ethylene yields without undergoing degradation and deactivation.
langue originale | Anglais |
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Numéro d'article | 110028 |
journal | Microporous and Mesoporous Materials |
Volume | 297 |
Les DOIs | |
Etat de la publication | Publié - 1 mai 2020 |
Financement
A.S. acknowledges funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 751774 . F.R.S.–F.N.R.S. is thanked for the acquisition of the physi-chemisorption equipment used here (project "EQP U.N030.18″). Authors acknowledge the ‘Communauté française de Belgique’ for the financial support through the ARC programme ( 15/20–069 ). This research used resources of the “Plateforme Technologique Physico-Chemical Characterization” – PC 2 , the SIAM platform (Synthesis, Irradiation & Analysis of Materials) and the MORPH-IM platform (Morphology & Imaging) located at the University of Namur. Authors thank L. Simonikova for performing ICP-OES analyses and V. Vykoukal for TEM micrographs. CIISB research infrastructure project LM2015043 funded by MEYS CR is gratefully acknowledged for the financial support of the measurements at the CF Cryo-electron Microscopy and Tomography and at the CF X-ray Diffraction and Bio-SAXS. This research has been financially supported by the MEYS CR under the project CEITEC 2020 ( LQ1601 ). François Devred and Jean-François Statsyns are acknowledged for the technical and logistical support. Marie Skłodowska-Curie grant agreement No 751774 . Marie Sk?odowska-Curie grant agreement No 751774.Communaut? fran?aise de Belgique, ARC programme 15/20?069.A.S. acknowledges funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sk?odowska-Curie grant agreement No 751774. F.R.S.?F.N.R.S. is thanked for the acquisition of the physi-chemisorption equipment used here (project "EQP U.N030.18?). Authors acknowledge the ?Communaut? fran?aise de Belgique? for the financial support through the ARC programme (15/20?069). This research used resources of the ?Plateforme Technologique Physico-Chemical Characterization? ? PC2, the SIAM platform (Synthesis, Irradiation & Analysis of Materials) and the MORPH-IM platform (Morphology & Imaging) located at the University of Namur. Authors thank L. Simonikova for performing ICP-OES analyses and V. Vykoukal for TEM micrographs. CIISB research infrastructure project LM2015043 funded by MEYS CR is gratefully acknowledged for the financial support of the measurements at the CF Cryo-electron Microscopy and Tomography and at the CF X-ray Diffraction and Bio-SAXS. This research has been financially supported by the MEYS CR under the project CEITEC 2020 (LQ1601). Fran?ois Devred and Jean-Fran?ois Statsyns are acknowledged for the technical and logistical support.
Bailleurs de fonds | Numéro du bailleur de fonds |
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Communauté française de Belgique | |
Marie Skłodowska‐Curie | |
fran?aise de Belgique | |
Horizon 2020 Framework Programme | 751774 |
Australian Government, Australian Research Council | 15/20–069, LM2015043 |
Ministerstvo Školství, Mládeže a Tělovýchovy | LQ1601 |
Horizon 2020 | EQP U.N030.18?, 069 |
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