Catalytic activity of La-modified TiO2 for soot oxidation by O2

TiO2 and La-doped TiO2 samples with La loading between 0.2% and 2% have been prepared, characterised, and tested in the catalytic oxidation of soot by O-2. La doping prevents anatase to rutile phase transformation and crystallite size growth when heated at 800 degrees C, as deduced from XRD, Raman spectroscopy and BET surface area measurements. The optimum La loading was found to be 0.2%. The catalytic activity of TiO2 and La-doped TiO2 samples tested mainly depends on crystallite size, the lower the size the better the activity. TiO2 phase composition is not a key factor in the catalytic oxidation of soot. (c) 2006 Elsevier B.V. All rights reserved.