Starting from colloidal TiO2 nanoparticles in combination with tetraethyl orthosilicate using neutral Pluronic or cationic cetyltrimethylammonium as templates, a series of structured mesoporous silicas has been obtained. The structure of the mesoporous titania was confirmed by isothermal gas adsorption, transmission electron microscopy, and X-ray diffraction. The pore diameter ranged between 3.8 and 10.9 nm, and the BET surface area varied from 99 to 584 m2 g(-1). The photocatalytic activity of these samples for the degradation of phenol in aqueous solution has been compared with that of standard P-25 TiO2. Even though the activity of these new mesostructured materials is lower that those found for P-25 TiO2, the turnover frequency of the photocatalytic activity (moles of phenol degraded per Ti atom present at initial reaction time) is much higher for the mesoporous titania, particularly with low titanium contents for those materials (mpTiO2-5 and TiO2SBA15-5).

A series of periodic mesoporous silicas of MCM-41 type containing varying amounts (5−50%) of chiral binaphthyl and cyclohexadiyl moieties occupying framework positions have been synthesized, and their characteristic MCM-41 features were observed by powder XRD and porosity measurements. The covalent bonding of the organics to the silicate framework was confirmed by 1H and 29Si MAS NMR experiments. Direct measurement of the optical activity demonstrates that the solids are able to rotate the angle of plane-polarized light. Also, a certain degree of chiral discrimination has been observed for the asymmetric enhancement of the binaphthyl fluorescence by adding enantiomerically pure 1,2-cyclohexadiamine.

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A urea-containing mesoporous silica with intraframework urea groups (UreaMS) was synthesized via a surfactant-templated route by co-condensation of an organosilane precursor and tetraethoxysilane. The material possesses hexagonal pores with a high degree of uniformity and shows long-range order as confirmed by the measurement of powder X-ray diffraction and N2 adsorption isotherms. A detailed characterization by chemical analysis, 29Si MAS NMR, X-ray photoelectron spectroscopy, thermogravimetric analysis, and FT-IR spectroscopy confirmed the integrity of urea groups inside the walls of the material. The results revealed a density of one urea group per ca. 13−16 silicon atoms. The efficiency of UreaMS for the adsorption of Fe(III) cations was tested. A distribution coefficient of K d = 700 mL g-1 and an adsorption capacity of 0.19 mmol g-1 were determined. X-ray photoelectron spectroscopy confirmed the conservation of the oxidation state +3 for the iron within the mesoporous silica material.