Synthetic routes for titania nanoparticles in the flame spray pyrolysis

Spherical TiO2 nanoparticles were synthesized from titanium(IV) isopropoxide (TTIP) precursor by flame spray pyrolysis. The effects of experimental variables such as the molar concentration of the precursor and the flow rate of hydrogen gas on the particle properties were analyzed by using TEM, XRD, and BET. As the precursor concentration increased from 0.1 to 1.0 M, the average primary particle diameter increased from 13 to 61 nm corresponding to 126 and 25 m(2)/g in the specific surface area, respectively. With a decrease in hydrogen flow rate from 5 to 31/min, the average primary particle size increased from 13 to 32 nm. From these results, the synthetic route of TiO2 nanoparticles in the flame spray pyrolysis was estimated and a mechanism for the particle formation and growth was suggested. (C) 2007 Elsevier B.V. All rights reserved.