Abstract: Porous SiO₂-TiO₂ blocks were successfully synthesized by polymerization of tetraethyoxysilane and tetrabutyl titanate in the presence of polyethylene glycol via a sol-gel route. Their infrared spectra,
pore distribution and chemical durability were mainly studied. The results showed that the residual organic component can be removed after heat-treated at 500℃ for 2h, and then a vitreous
structure with Si-O and Ti-O bonds was formed. The porous materials containing Ti had a narrower pore distribution and the peak of the pore distribution curve shifted to the smaller pore diameter.
With the increase of TiO₂ content, the density of porous blocks increased, whereas open porosity and adsorbed water ratio decreased at the same time. After immersion in water at 80℃ for
72h, the type and shape of adsorption-desorption curves changed slightly. Since the change of specific surface area, pore volume and average pore diameter for the obtained materials decreased with the
increase of Ti content, it indicated an improvement of water resistance. The durability of porous blocks in 1% NaOH basic solutions at 95℃ was apparently improved due to an addition of titanium
as compared with SiO₂ porous block which was collapsed in such solution. However, anti-acid resistance of porous materials in 20% H₂SO₄ solutions at 98℃ can not be improved by an addition of titanium.

Key words: sol-gel process, organic-inorganic hybrid, porous SiO₂-TiO₂, chemical durability