| Due to the potential of simultaneously reducing particulate matter (PM) and nitrogen oxides (NOx) emissions, non-thermal plasma coupled with catalytic diesel particulate filter technology (NTP/CDPF) has been given more attentions for its application on the exhaust aftertreatment systems. In the present study, the prototype catalyst combined with highest activity was screened out through the characterization and catalytic activity evaluation of La-K-Co-Fe perovskite-type catalysts and catalytic reaction mechanism was discussed. Also, the removal effects of NTP on diesel exhaust emissions are investigated. The practical application of NTP/CDPF system on diesel exhaust emissions are performed on a bench test, and the influences of NTP and the catalysts on the regeneration temperature of diesel particulate matters were studied The investigations will benefit the further use of NTP/CDPF system and provide a theoretical foundation.The major conclusions of this dissertation can be summarized as follows:1. The partial substitution of K, Fe for La, Co in LaCoO3 respectively results in perovskite cell deformation and can oxidize a part of Co2+<sup>3+ at B site to Co3+.2. La1-xKxCoO3 is able to significantly reduce the temperature at which the soot combustion rate is maximum (Tmax) and reaction activation energy (Ea) of soot oxidation with O2, while LaFeyCo1-yO3 has little influence on the reaction. Among them, La0.6K0.4CoO3 can decrease Tmax to 400℃and Ea to 41.6kJ/mol. Both La1-xKxCo1-yFeyO3 (x≤0.5) and LaFeyCo1-yO3 (y≤0.7) can decrease Ti (temperature at which the soot ignites) and Tp (temperature at which CO2 concentration is the highest) values in NOx atomsphere. Among all the developed perovskite-type catalysts, La0.9K0.1CoO3 is discovered to have the highest catalytic activity in simultaneous reduction of PM and NOx emissions, it could decrease Ti to 100℃and Tp to 105℃3. For NOx removal, the dopant and doping amount play an important role on the reduction efficiency and the effective temperature window of these catalysts. La1-xKxCoO3 (0.1≤x≤0.5) exhibits higher catalytic activity in the range of 375℃～ 525℃, while LaFeyCo1-yO3 (0.1≤y≤0.6) shows higher catalystic activity in the range of 275℃375℃. La0.7K0.3CoO3 and LaFe0.5Co0.5O3 could produce 50% reduction in NOx respectively.4. By means of NTP,75% reduction in NOx occur at lower input energy (voltage: 7.5kV), while the removal efficiencies of PM and CO are rather low. With increasing of the input energy to 10kV, the use of NTP leads to an increase of NOx concentration in exhaust gas, however PM, dry soot, SOF, aromatic, PAHs and HC are efficiently removed with removal efficiencies of 86%, 100%, 80%, 90%, 65% and 83% respectively. The trade-off between NOx and other pollutants exists when altering the input energy of NTP.5. NTP/CDPF system is available to abate the toxic exhaust emissions, such as NOx,PM,HC and CO, from diesel engine. Under the engine operation conditions selected, the reductions in PM, NOx, HC and CO reach 82%, 31%, 88% and 12% respectively. Meanwhile, the removal efficiencies decrease with enhancing the space velocity in the system.6. Regeneration method, PM mass trapped in the DPF and catalyst type are the most important factors to control the Treg of DPF, and NTP could decrease the Treg of perovskite-type DPF to 300.5℃.
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