Formation of titania nanofibers:: A direct sol-gel route in supercritical CO2

In this letter, we present a new method to synthesize titania nanofibers with nanocrystallites via a sol-gel route in supercritical CO2. The nanofibers were formed by the esterification and condensation of titanium alkoxides using acetic acid as the polymerization agent in supercritical CO2 from 40 to 70 degrees C and 2500 to 8000 psia. The TiO2 nanofiber morphology was characterized by means of SEM and HRTEM, which indicated that the diameters ranged from 9 to 100 nm. N-2 physisorption, and powder XRD showed that the nanofibers exhibited relatively high surface areas up to 400 m(2)/g and anatase and/or rutile nanocrystallites were formed after calcination.