Highly active MnOx-CeO2 catalyst for diesel soot combustion

A series of MnOx-CeO2 composites have been prepared via a facile coprecipitation method and used as catalysts for diesel soot combustion. It is found that the content of manganese oxide has a considerable influence on both the morphology and catalytic activity for diesel soot combustion in the copresence of NOx and O-2. Superior catalytic activity (T-f = 360 degrees C) was obtained over the optimized catalyst CM20 [Mn/ (Mn + Ce) equals to 20 at%], which is believed to be attributable to the following two aspects: (1) the abundant pore structure, presenting between the loosely-packed homogeneous particles with similar sizes to that of the soot particles, which is beneficial for mass transfer and heat diffusion as well as the sufficient contact between catalyst and soot; (2) high concentration of Mn4+ and Ce3+ cations derived from the charge transfer between Mn and Ce species as active sites can adsorb and activate NO and O-2, and then greatly facilitate NO2 production.