Preparation of Carbon-Doped TiO2 Nanopowder Synthesized by Droplet Injection of Solution Precursor in a DC-RF Hybrid Plasma Flow System

Carbon-doped titanium dioxide nanopowder has received much attention because of its higher photocatalytic performance, which is practically activated not only by UV, but also by visible light irradiation. In the present study, C-TiO 2 nanopowder was synthesized by droplet injection of solution precursor in a DC-RF hybrid plasma flow system, resulting in higher photocatalytic performance even under visible light irradiation. In-flight C-TiO 2 nanoparticles reacted with the high concentration of carbon in plasma flow and were then deposited on the surfaces of two quartz tubes in the upstream and downstream regions of this system. The collected C-TiO 2 nanopowder contained anatase-rutile mixed-phase TiO 2 and TiC, the contents of which depended on the location of the powder collection, the temperature, and the duration of plasma treatment. Highly functional C-TiO 2 nanopowder collected in the downstream region exhibited a higher degradation rate of methylene blue than that of single-phase anatase TiO 2 , even under visible light irradiation, in spite of being TiC.