Preparation of mesoporous titania in the presence of hydrophilic polymer

Titanium tetra-isopropoxide (TTIP) was dissolved in hydrochloric acid solut ion to prepare a transparent titania sol solution. Titania precipitates wer e obtained by aging a mixed solution of the titania sol and a hydrophilic p olymer for 24 hours at 60 degreesC. In the presence of polyacrylacid (PAA), gelation or precipitation is occurr ed depending on the concentration of PAA and TTIP. White powders of titania were obtained by calcination of the gel or precipitation. These powders we re anatase type with specific area larger than 100m(2)/g. The titania obtai ned via gelation is anatase mesoporous titania, which possesses a sharp pea k of pore size distribution. A peak is observed in the low angle of XRD pat tern for both as-synthesized and calcined mesoporous titania. The result su ggests that titania has a regular nano-structure, which is retained after c alcination. In the polyethyleneglycol (PEG) system, no gelation of the solution took pl ace under these experimental conditions. The titania powder became rutil-ty pe with increasing in the concentration of PEG. Both specific area and pore volume of the titania powder decreased. Furthermore, the pore size distrib ution of the titania is broader than that of the PAA system.