Abstract: The nanometric LaBO3(B=V, Cr, Mn, Fe, Co, Ni, Cu) oxides were prepared by the organic acid ligation method. The samples were characterized by the techniques of XRD, UV-Vis, FT-IR, H2-TPR, and SEM. The catalytic performance of the prepared samples for the simultaneous removal of soot and NO emitted from diesel engines was investigated. The results showed that the synthesized LaBO3 (B=Cr, Mn, Fe, Co, Ni) oxides possess perovskite-type structures except for La-Cu-O and La-V-O. The oxidizing ability of these five perovskite oxides follows the order of LaNiO3≈LaCoO3＞LaMnO3＞LaFeO3＞LaCrO3, which is consistent with their activity sequence for the desired reactions. Thus their catalytic performance is closely related to the oxidizing ability of these perovskite oxides. Among them, LaCoO3 and LaNiO3 have higher activities for the simultaneous removal of soot and NO. The combustion temperatures (Tm) of soot particles over them are 421 and 431 ℃, respectively, when the contact between catalysts and soot are loose. The selectivities of CO2 are 99.1% and 99.7%, and NO conversions are 17.2% and 20.1%, respectively.

Key words: diesel exhaust, perovskite-type oxide, carbon particulate, nitrogen oxide, B-site cation