Synthesis and characterization of new silica–titania mixed oxide in the presence of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide by sol–gel technique

Silica–titania mixed oxide were prepared by sol–gel method from tetraethylorthosilicate and titanium (IV) isopropoxide as precursors in the presence of room temperature ionic liquid (RTIL), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide [C₄MIm][NTf₂]. The effects of [C₄MIm][NTf₂] on the structural and textural characteristics of silica–titania matrix are investigated in this paper. The materials obtained were well characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis X-ray powder diffraction (XRPD), field emission scanning electron microscope (FESEM) and N₂ adsorption–desorption analysis. It is believed that the [C₄MIm][NTf₂] plays an important role as a template and the high surface area of the samples is thought to mainly attribute to the formation of microporous in the reaction. The synthesized materials showed the presence of C–N groups in the FTIR spectrum which indicates the presence of RTIL in the silica–titania matrix. XRPD, FESEM and N₂ adsorption–desorption analysis results indicated that the composite materials possessed good microporous character. The subsequent material displayed average pore diameter of 1.70–2.12 nm, pore volume of 0.08–0.19 cm³/g and BET surface area of 191–386 m²/g. Increasing the content of RTIL resulted in an increase of the average pore diameter of the silica–titania gel.