Synthesis of mesoporous nanocrystalline titania powders by nonhydrolitic sol-gel method

Abstract

Mesoporous titania with well-crystallized anatase phase was synthesized by nonhydrolytic sol-gel process combined with solvothermal treatment. Titanium-isopropoxide, titanium-tetrachloride, and carbon-tetrachloride were used for synthesis under nitrogen atmosphere in a glove box. The obtained mixture was heated in an autoclave at 140 degrees C for 3 h and 30 h. XRD analysis showed that dry gels contained anatase phase with low crystallinity, while powders obtained by calcination of dry gels at 500 degrees C for 3 h consisted of pure anatase with high crystallinity. SEM analysis of dried gels and powders shows agglomerates of spherical particles of the size similar to 300 nm. The TEM micrographs confirmed the nanoscale size of the titania powders, with the primary particle size of about 20 nm. Titania powders exhibit maximum pore diameter of 13.2 nm and 9.5 nm for gelation time 3 h and 30 h, respectively. The photocatalytic activity of such synthesized titania is superior to that of commercial photocatalyst Degussa P-25.