Preparation And Performance Of LiCoO₂ For Simultaneously Catalytic Removal Of Soot And NO_x

Diesel engine has been widely used for years due to high fuel economy performance, stability and durability. However, the Particulate Matter?PM? and Nitric O_xides?NO_x? from exhausted gas have great influence on human's health. Besides, in order to meet the strict emission regulations, exhausted gas treatment has arosed great attention.LiCoO₂ catalysts were parpared by solution combustion synthesis method?SCS? and high temperature solid-state method?HTSM? in this paper. Carbon black was used to simulate Particulate Matter in diesel engine exhaust. Temperature programmed technology was used to investigate the catalytic performance of the prepared catalysts. The influence of catalyst preparation methods and crystal structure on the performance had been discussed in this paper. The research work mainly included the following parts:Experiments were conducted to investigate the performance of simultaneous catalytic removal of PM and NO_x. It was showed that all the catalysts with different synthetic method had active effects on the removal of PM and NO_x. Compared with high temperature solid-state method, catalysts prepared by solution combustion synthesis method had a better performance. The ignition and maximum combustion temperature of the catalyst prepared by solution combustion method in 500 oC were 272 oC and 312 oC respectively.Different fuel, amount of fuel, synthesis temperature and heat preservation had been studied to realize the influence on catalytic performance of simultaneously removal of PM and NO_x of the catalysts prepared by solution combustion method. The results showed that the catalyst had a better catalystic performance on simultaneously removal of PM and NO_x when the synthesis temperature was 600 oC, urea was doubled compared with stoichiometric ratio and the heat preservation was 35 mins. The ignition and maximum combustion temperature, conversion efficiency of NO_x to N2 and selectivity of N2 were 270 oC, 310 oC, 36.9% and 77.3% respectively.NaCl and C2H2O4 as the additives were added during the synthesis process in solution combustion method to improve the catalytic performance on simultaneously removal of PM and NO_x. Different amount of NaCl and C2H2O4 were used for the further investigation. It was found that the additive could increase the surface area and the surface adsorption oxygen species, which improved the contact area between carbon black and catalysts during catalytic reaction. When NaCl was added as half weight of the catalyst during the synthesis process, the prepared catalyst had the best catalytic performance with the lowest ignition and maximum combustion temperature 246 oC, 282 oC respectively. There was no obvious difference in conversion effiency of NO_x to N2 when additives were added, which may be decieded by the nature of the material itself.