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The active phase Ce 0.5 Pr 0.5 O 2 has been loaded on commercial substrates (SiC DPF and cordierite honeycomb monolith) to perform DPF regeneration experiments in the exhaust of a diesel engine. Also, a powder sample has been prepared to carry out soot combustion experiments at laboratory. Experiments performed in the real diesel exhaust demonstrated the catalytic activity of the Ce-Pr mixed oxide for the combustion of soot, lowering the DPF regeneration temperature with regard to a counterpart catalyst-free DPF. The temperature for active regeneration of the Ce 0.5 Pr 0.5 O 2 -containing DPF when the soot content is low is in the range of 500-550 ºC. When the Ce 0.5 Pr 0.5 O 2 -containing DPF is saturated with a high amount of soot, pressure drop and soot load at the filter reach equilibrium at around 360 ºC under steady state engine operation due to passive regeneration. The uncoated DPF reached this equilibrium at around 440 °C. Comparing results at real exhaust with those at laboratory allow concluding that the Ce 0.5 Pr 0.5 O 2 -catalysed soot combustion in the real exhaust is not based on the NO 2 -assisted mechanism but is most likely occurring by the active oxygen-based mechanism.

Ce0.64Zr0.27Nd0.09O δ mixed oxides have been prepared by three different methods (nitrates calcination, coprecipitation and microemulsion), characterized by N2 adsortion, XRD, H2-TPR, Raman spectroscopy and XPS, and tested for soot combustion in NOx/O2. The catalyst prepared by microemulsion method is the most active one, which is related to its high surface area (147 m 2 /g) and low crystallite size (6 nm), and the lowest activity was obtained with the catalyst prepared by coprecipitation (74 m 2 /g; 9 nm). The catalyst prepared by nitrates precursors calcination is slightly less active to that prepared by microemulsion but the synthesis procedure is very straightforward and surfactants or other chemicals are not required, being very convenient for scaling up and practical utilization. The high activity of the catalyst prepared by nitrates calcination can be attributed to the better introduction of Nd cations into the parent ceria framework than on catalysts prepared by coprecipitaion and microemulsion, which promotes the creation of more oxygen vacancies.