Study On Purifying Automobile Exhaust By High-efficiency Catalyst With Plasma

Vehicle exhaust emissions have become one of the main sources of air pollution.VOCs,NOx and other pollutants contained in it are the“raw materials”of secondary organics and nitrates,and they are also important“catalysts”that enhance atmospheric oxidation.At present,independent three-way catalysts are facing problems including low catalytic activity,narrow temperature range,thermal failure and poisoning failure,and they are unable to meet increasingly stringent automotive exhaust emission standards.Therefore,secondary treatment of automotive exhaust is very necessary.In this paper,a three-stage detachable automobile exhaust purification device is designed.The first stage is the plasma discharge part,the middle part is the expansion part,and the tail part is the catalytic conversion part.The mechanism of purifying automobile exhaust by high-efficiency catalyst with plasma was studied A high-efficiency catalyst was prepared by using zirconium-cerium solid solution as a carrier,lanthanum as a catalyst auxiliary agent,nano-aluminum sol as a catalyst coating,Ba O as a stabilizer of the aluminum sol,and Pd as an active component of the catalyst.The co-precipitation method is used to provide solid solutions with different cerium-zirconium ratios as catalyst carrier.When the cerium-zirconium ratio is 1:2,the specific surface area is the largest,reaching 113.4m²/g.Lanthanum is used as a catalyst auxiliary component.When its amount is 6%of the mass of cerium-zirconium solid solution,the catalyst has the best catalytic effect.Pd is the active component of the catalyst.When the amount of Pd is 0.6%of the catalyst mass,the catalytic efficiency and specific surface area of the catalyst are the best.The nano-aluminum sol with Ba O as the stabilizer is used as the coating of the catalyst.When the mass fraction of Ba O is 8%,the catalyst has the best thermal stability under high temperature conditions.The influence of plasma on NOx was studied by using a single electrode,and the efficiency of NOx removal was experimented by changing tube diameter,wire diameter,and applied voltage.The results show that the conversion efficiency of NO is obviousat 40mm pipe diameter and 0.8mm thorn line.The conversion rate of NO to NO₂is 14.38%,and the conversion rate of NO to N₂is 31.15%.The catalytic efficiency of NO can reach 78%by using a high-efficiency catalyst,composed of zirconium-cerium solid solution as carrier,lanthanum as an auxiliary agent,palladium as an active component,and Ba O as an aluminum sol stabilizer,with plasma.