**2.3. Silylation of H+-titanosilicate**

DDA–OTES mixed solutions were prepared by dissolving OTES and DDA in ethanol (95%). The concentration of OTES in solution was between 0.01 and 0.1 M, and the DDA concentration was held constant at 0.1 M. H+-titanosilicate(DDA–OTES–TS) with intercalated OTES and DDA preparation H+-titanosilicate (0.321 g, 0.5 mmol) was then dispersed in 6 mL (0.01, 0.05, 0.1 M OTES 3 mL + 0.1 M DDA 3 mL) of these solutions (ultrasound, 20 min, at room temperature) and evaporated and dried for 24 h at 50 oC. OTES–TS was recovered by filtering, washed with ethanol until free of DDA using DDA– OTES–TS, and then dried in the air at 50 oC.
