【Abstract】 As catalytic materials, nanometer rare earth perovskites LaMnO₃ were prepared by NaOH-Na₂CO₃ coprecipitation, followed by supercritical drying, vacuum drying and air drying respectively. The effect of drying processes was studied on the catalyst performance through XRD, TEM, SEM and BET analysis. The results demonstrated that about 30 nm LaMnO₃ particles could be prepared by three drying processes respectively. The catalyst materials LaMnO₃ dried in vacuum presented the largest specific surface area as 28.71 m²·g^{－ 1}. Compared to the catalyst prepared by dipping cordierite directly in the salt solutions, nanometer LaMnO₃ showed better catalytic activity. The light-off temperatures for CO and HC oxidation were both lowered by 100℃ , and its NO_x conversion could be up to 100％ at 570℃ .更多还原