Rare earth (La, Nd, Pr) doped ceria zirconia solid solutions for soot combustion

A series of rare earth (RE) (La, Nd, Pr) ceria
zirconia materials were analysed for their soot combustion
activity in air and in NO/O2. The materials were characterised
using DRIFT spectroscopy. In general the presence
of the RE dopant increases the activity of undoped
CexZr1-xO2. The La and Pr doped catalysts showed
increased low temperature activity in the presence of NO/O2
while the effect was less pronounced in case of Nd - doped
samples. FTIR data has shown that the catalysts interact
differently to NO/O2 mixtures in that they do not form significant
quantities of adsorbed nitrite-type species. We postulate
that this species is a precursor to NO2 formation which
in turn increases soot combustion.