Studies On Plasma Promoting Effect Of Cu_0.05Ce_0.95O Catalyst For Soot Combustion

Compared with gasoline engines, Diesel engines are widely used in many countries allover the word for the advantage of dynamic and energy-saving.However, the pollutants ofdiesel engines exhaust, especially PM, bring a large load to the environment. In recent years,Plasma Assisted Catalytic technology has made great progress in academic research andindustrial applications. The discharge can produce large amounts of free radicals, which canoxidize diesel particulate matter in the lower exhaust temperatures. The plasma is oftenassociated with SCR technology to promote the efficiency of NO_xremoving and selectivity.The research of removing the PM by plasma is lacked comparing to the NO_x’s. Based onthese points, in this paper the impact on the performance of catalytic soot combustion and thestrengthening role is focused on.CuO^-CeO₂, as a ideal diesel-exhaust-controlling catalyst, has wonderful catalyticbehavior and economical efficiency for soot combustion. On the basis of preliminary studies,the study of the surface species on the catalysts and promoting effect of plasma of Catalyst forSoot Combustion, is mainly discussed.The main conclusion were concluded after the study:（1） Cu_0.05Ce_0.95-CA still has formed a cubic phase fluorite structure,and the Oxygenvacancies are greatly formed on the catalyst surface. Compared with no catalysts,Cu_0.05Ce_0.95-CA can deeply decrease ignition temperature, maximum oxidation ratetemperature and complete combustion temperature. Meanwhile, it can improve theoreticalefficiency and selectivity.（2） By plasma, the activity for soot combustion is much greater, and the theoreticalefficiency is much better. The carbonaceous deposits on the catalyst is effectively controlled.（3） Cu_0.05Ce_0.95-CA has smaller average crystallite diameter, larger specific surface areaand larger pore volume by plasma. When the dissociative CuO turns into the dispersive CuO,more Cu²⁺ions enter the lattice CeO₂and more Cuy²⁺Ce1-y⁴⁺O_2-y^2-□_yare formed. At the sametime, the redox couple (Ce⁴⁺/Ce³⁺) is oscillated and the oxygen storage capacity is greatlyenhanced. Due to these results，more reactive oxygen species is generated. The oxygenspecies（O₂^-、O^-�'�O₂^-）’ fluxion, movement and transmission can promote the growth ofoxygen vacancies circularly by plasma, which can improve the catalytic activity for sootoxidation persistently.