Influences of A- or B-site substitution on the activity of LaMnO_3 perovskite-type catalyst in oxidation of diesel particle

摘要

LaMnO_3 was partially substituted at A- or B-site by Sol-Gel method and characterized by XRD, SEM and BET. Perovskite oxides were formed in all substitutions. The catalytic activities of substituted catalysts on carbon black oxidation were measured by Temperature Programming Oxidation (TPO). Experimental results showed that all substitutions increased the catalytic activity of LaMnO_3, and La_(0.8)Cs_(0.2)MnO_3 showed the highest catalytic activity. Under tight contact, the activity enhancement of different substitutions decreased in the order Cs>K>V>Ce>Co>Cu>Fe. Dynamic analysis showed that partial substitutions increased the pre-exponential factor and the catalytic activity by increasing the oxygen vacancy on the catalyst surface. The active components on the surfaces of La_(0.8)Ce_(0.2)MnO_3 and LaMn_(0.8)V_(0.2)O_3 included CeO_2 and LaVO_4, which changed the apparent activities and dynamic parameters of these two catalysts.