Perovskite catalyst (La, Ba)(Fe, Nb, Pd)O3 applicable to NOx storage and reduction system

We have developed a perovskite catalyst, (La0.7Ba0.3)(Fe0.776Nb0.194Pd0.03)O3, applicable to the NOx storage-reduction system. The perovskite catalyst exhibits 47% of NOx conversion rate at 523 K under the 54–6 s alternation of the lean–rich-burning where the lean and rich gases contain 512 ppm NO + 5 vol.% O2 and 512 ppm NO + 4 vol.% CO, respectively. The base perovskite, LaFe0.97Pd0.03O3, was endowed with a NOx adsorbing capability by partially substituting Ba for La in the A-site of ABO3 structure. Partially replacing Fe in the B-site with pentavalent transition metals (Nb, V and Ta) was also required to develop the NOx-reducing ability.