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

Abstract We have developed a perovskite catalyst, (La 0.7 Ba 0.3 )(Fe 0.776 Nb 0.194 Pd 0.03 )O 3 , applicable to the NO x storage-reduction system. The perovskite catalyst exhibits 47% of NO x 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.% O 2 and 512 ppm NO + 4 vol.% CO, respectively. The base perovskite, LaFe 0.97 Pd 0.03 O 3 , was endowed with a NO x adsorbing capability by partially substituting Ba for La in the A-site of ABO 3 structure. Partially replacing Fe in the B-site with pentavalent transition metals (Nb, V and Ta) was also required to develop the NO x -reducing ability.