Preparation of mesoporous titania in the presence of hydrophilic polymer

Titanium tetra-isopropoxide (TTIP) was dissolved in hydrochloric acid solution to prepare a transparent titania sol solution. Titania precipitates were obtained by aging a mixed solution of the titania sol and a hydrophilic polymer for 24 hours at 60 degreesC. In the presence of polyacrylacid (PAA), gelation or precipitation is occurred depending on the concentration of PAA and TTIP. White powders of titania were obtained by calcination of the gel or precipitation. These powders were anatase type with specific area larger than 100m(2)/g. The titania obtained via gelation is anatase mesoporous titania, which possesses a sharp peak of pore size distribution. A peak is observed in the low angle of XRD pattern for both as-synthesized and calcined mesoporous titania. The result suggests that titania has a regular nano-structure, which is retained after calcination. In the polyethyleneglycol (PEG) system, no gelation of the solution took place under these experimental conditions. The titania powder became rutil-type with increasing in the concentration of PEG. Both specific area and pore volume of the titania powder decreased. Furthermore, the pore size distribution of the titania is broader than that of the PAA system.