This study examined the synthesis of carbon-doped titanium dioxide using TiCl4 and CO2 as titanium and carbon sources, respectively, by thermal plasma at atmospheric pressure. The effect of the CO2 gas flow rate on the preparation of TiO2 was investigated. The results showed that the decomposition rate of CO2 was 90% at a CO2 gas flow rate of 1 L/min. When TiCl4 was added to produce TiO2, the decomposition rate of CO2 reached 95% at a CO2 gas flow rate of 1 L/min. The resulting powders contained mixed anatase and rutile phases with particle sizes ranging from 20 to 50 nm. The carbon in the CO2 acted as a dopant to produce the carbon-doped TiO2. The prepared samples were mainly characterized by X-ray diffraction, X-ray photoelectron spectroscopy, specific surface area measurements and ultraviolet-visible spectroscopy. (C) 2009 Elsevier B.V. All rights reserved.