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Ind. Eng. Chem. Res. 2007, 46, 6264-6268
Preparation of Crystalline Mesoporous Titania Using Furfuryl Alcohol as Polymerizable Solvent Jianfeng Yao and Huanting Wang* Department of Chemical Engineering, Monash UniVersity, Clayton VIC3800, Australia
This paper presents the preparation of crystalline mesoporous titanias using furfuryl alcohol as a polymerizable solvent and titanium(IV) butoxide as a titania source. In the synthesis, furfuryl alcohol (FA) initially stabilized titanium(IV) butoxide through alcohol exchange reaction, and then highly crosslinked poly(furfuryl alcohol) (PFA), formed via thermal polymerization of FA, served as a temporary barrier to confine titania crystallization. The crystalline mesoporous titanias were finally obtained by removing PFA and organic surfactant. X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and N2-sorption were used to characterize the crystalline mesoporous titanias. The characterizations showed that the crystalline mesoporous titanias prepared under different conditions possessed pore sizes of 11.1-23.6 nm and Brunauer-Emmett-Teller (BET) surface areas of 26.1-109.9 m2/g. The pore size and surface area of crystalline mesoporous titania increased when the ratio of titanium(IV) butoxide to furfuryl alcohol decreased. 1. Introduction Considerable efforts have been directed to the synthesis of mesoporous titania because of their broad range of applications such as gas sensors, photocatalysts, photovoltaic cells, pigments, and optical coatings.1-4 Titanium alkoxides and titanium chloride are commonly used as titania precursors to prepare mesoporous titania structures with organic surfactants such as block copolymers5-9 and alkylamines as the templates.10 Organic solvents such as ethanol, butanol, ethylene glycol, and benzyl alcohol are usually used to control the sol-gel process during the mesostructure formation since these titania precursors are highly reactive.1-7 Owing to the exchange reaction between titania precursors and alcoholic solvents, alcoholic solvents are very effective in slowing down the hydrolysis of the titania precursors.2 Crystalline mesoporous titanias are usually obtained by crystallizing titania frameworks at high temperatures (e.g., 500 °C), while the organic templates used in the synthesis are burned off at relatively low temperatures. The reorganization of titania frameworks during the crystallization may lead to shrinkage or even collapse of mesoporous structures in the absence of organic surfactant. The crystalline mesoporous titanias with a pore size of
