Toward a Low-Temperature Sol−Gel Synthesis of TiO2(B) Using Mixtures of Surfactants and Ionic Liquids

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• 作者：Helena Kaper ; Sbastien Sallard ; Igor Djerdj ; Markus Antonietti ; Bernd M. Smarsly
• 刊名：Chemistry of Materials
• 出版年：2010
• 出版时间：June 8, 2010
• 年：2010
• 卷：22
• 期：11
• 页码：3502-3510
• 全文大小：917K
• 年卷期：v.22,no.11(June 8, 2010)
• ISSN：1520-5002

文摘

An approach toward the synthesis of nanocrystalline TiO₂(B) in surfactant/ionic liquid systems at low temperature (100 °C) by means of sol−gel chemistry is presented. As reaction medium, a solution of imidazolium- and ammonium-based surfactants in ionic liquids was applied. Interestingly, TiO₂(B), in coexistence with anatase, was observed only in cases where the ionic liquid is based on imidazolium moieties. The final product contained up to 60 wt % TiO₂(B), depending on the initial amount of surfactant. X-ray powder diffraction measurements and transmission electron microscopy revealed small particle sizes (ca. 2 nm for TiO₂(B), around 6 nm for anatase) as well as a high crystallinity of the material. The materials possessed surface areas up to 300 m²/g. Electrochemical studies further confirmed the presence of the two titania polymorphs anatase and TiO₂(B) in similar proportions. Small-angle X-ray scattering experiments gave insight into the phase behavior of the surfactant in the ionic liquid under reaction conditions. The formation of TiO₂(B) is discussed based on systematic variation of diverse parameters.