Incorporation of titanium and titanium–iron species inside a smectite-type mineral for photocatalysis

The present paper reports the modification of a clay mineral by the incorporation of TiO2 (anatase) and iron–TiO2 species to obtain delaminated solids with photocatalytic activity under very low intensity UV irradiation. The materials were characterised by X-ray fluorescence, X-ray diffraction, scanning electron microscopy, N2 adsorption and IR spectroscopy confirming the effective insertion of TiO2 in the clay mineral. The solids were catalytically tested in the total degradation of phenol in aqueous solution under mild conditions (25 °C and atmospheric pressure) showing that the photoactivity of the TiO2/clay system can be enhanced or reduced by incorporating iron depending on the method of preparation. Simultaneous incorporation of Fe3+ and Ti4+ from cationic solutions forms TiO2 nanoparticles in which the iron seems to be included in the anatase structure by isomorphic substitution with the consequent improvement of the photocatalytic activity.