Web Release Date: December 6,
Chlorinated Nanocrystalline TiO2 Powders via One-Step Ar/O2 Radio Frequency Thermal Plasma Oxidizing Mists of TiCl3 Solution: Phase Structure and Photocatalytic Performance
and
Nano Ceramics Center, National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044, Japan, Department of Materials Science, Hosei University, Kajino 3-7-2, Koganei 184-0002, Tokyo, Japan, and Nanoscale Materials Center, National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044, Japan
Received: September 12, 2007
In Final Form: October 10, 2007
Abstract:
Chlorinated TiO2 powders of high crystallinity and good dispersion have been synthesized via one-step Ar/O2 radio frequency thermal plasma oxidation of atomized aqueous solutions of TiCl3. The resultant powders
are anatase/rutile mixtures (~66-72 wt % of anatase), with particle sizes ranging from ~5 nm to 5 
m.
Detailed studies via X-ray diffraction and Raman spectroscopy on the nanometric (<100 nm) and the coarser
particles revealed weak dependence of the phase constituent and chemical stoichiometry on the size distribution
or the O2 input (5-90 L/min). Simultaneous incorporation of chlorine into the TiO2 lattice was confirmed by
thermal desorption and UV-vis spectroscopies. The chlorinated TiO2 powders exhibit narrowed indirect band
gaps of ~2.65 eV and enhanced UV absorption and, thus, show substantially higher photocatalytic activities
than Degussa P25 in the degradation of methyl orange solutions under both visible-light and UV illumination.
Download the full text: PDF | HTML
