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 O2. La doping prevents anatase to rutile phase transformation and crystallite size growth when heated at 800 °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.