Study On The Laser Ablation Synthesis Of LaMn_1-x（Pt/Pd）_xO₃ Catalysts And The Catalyticcombustion Of Diesel Soot Particulate

Diesel soot particles（PM）,resulting the growing environmental problems in recent years,is the main culprit of haze.Perovskite-type oxides play an important role in diesel exhaust removal.In this thesis,the physic-chemical properties of perovskite-type LaMn O₃ catalysts,doped by precious metals or ablating by pulsed laser in liquid medium,are characterized by SEM,TEM,XRD,XPS,H₂-TPR and TG-DSC.The catalytic activity of these supported catalysts for diesel soot removal studied in Thermogravimetric analyzer under the simulated diesel exhaust conditions.This study will provide some guidance for perovskite-type oxides used in the removal of diesel soot.Several conclusion have been drawn:（1）LaMn O₃ synthesized by the newly-developed sol-gel method have a high BET specific surface area（13m²/g）,a less crystalline size（100nm）and a higher activity for soot oxidation（T_m=428℃）.（2）The method that perovskite-type LaMnO3 catalyst is doped by precious metals Pt will cause the rising of 10%soot conversion rate temperature(T₁₀),the maximum rate temperature（T_m）and the 90%soot conversion rate temperature(T₉₀).Theoxides of noble metal have not a better catalytic activity than itself.（3）Pulsed laser ablation in liquid medium will destroy the perovskite crystal structure.Amorphous catalysts ablating by pulsed laser in liquid have an indistinctly promotion in catalytic activity at a relative low temperature.