Hierarchically Organized Silica–Titania Monoliths Prepared under Purely Aqueous Conditions |
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| Authors: | Dr. Sylvia Flaig Dr. Johanna Akbarzadeh Dr. Paolo Dolcet Dr. Silvia Gross Prof. Dr. Herwig Peterlik Prof. Dr. Nicola Hüsing |
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| Affiliation: | 1. Materials Chemistry, Paris‐Lodron University Salzburg, Hellbrunnerstrasse?34, 5020 Salzburg (Austria), Fax: (+43)?662‐8044‐622;2. Faculty of Physics, University of Vienna, Strudlhofgasse?4, 1090 Vienna (Austria);3. IENI‐CNR, Dipartimento di Scienze Chimiche, Università degli Studi di Padova via Marzolo?1, 35131 Padova (Italy) |
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| Abstract: | Hierarchically organized silica–titania monoliths were synthesized under purely aqueous conditions by applying a new ethylene glycol‐modified single‐source precursor, such as 3‐[3‐{tris(2‐hydroxyethoxy)silyl}propyl]acetylacetone coordinated to a titanium center. The influence of the silicon‐ and titanium‐containing single‐source precursor, the novel glycolated organofunctional silane, and the addition of tetrakis(2‐hydroxyethyl)orthosilicate on the formation of the final porous network was investigated by SEM, TEM, nitrogen sorption, and SAXS/WAXS. In situ SAXS measurements were performed to obtain insight into the development of the mesoporous network during sol–gel transition. IR‐ATR, UV/Vis, XPS, and XAFS measurements showed that up to a Si/Ti ratio of 35:1, well‐dispersed titanium centers in a macro‐/mesoporous SiO2 network with a specific surface area of up to 582 m2 g?1 were obtained. An increase in Ti content resulted in a decrease in specific surface area and a loss of the cellular character of the macroporous network. With a 1:1 Si/Ti ratio, silica–titania powders with circa 100 m2 g?1 and anatase domains within the SiO2 matrix were obtained. |
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| Keywords: | mixed oxides porous monoliths silica sol– gel process titania |
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