INFLUENCE OF THE AMOUNT OF TITANIA ON THE TEXTURE AND STRUCTURE OF TITANIA-SUPPORTED ON SILICA

Samples obtained by grafting various amounts of titania over silica us ing titanium IV isopropoxide in isopropyl alcohol were studied using S BET, pore volume, XRD, ESCA, DRS, and zeta potential measurements. Ver y good dispersion of TiO2 over silica approaching monolayer dispersion was observed for TiO2 content lower than about 15 wt%. At higher TiO2 content, TiO2 crystallites were formed. A strong oxide-oxide interact ion with the formation of the Ti-O-Si bend was observed. For a part of TiO2, the intensity of this interaction increases with the calcinatio n temperature, but for other parts, formed crystallites. (C) 1996 Acad emic Press, Inc.