Research On Perovskite Type Four-way Catalyst

The advantages of high efficiency and power of diesel engines have resulted in widely use in recent years. However, traditional low-emission technology was difficult to comprehensively control exhaust emissions, especially nitrogen oxides and particulate matter hazards. Four-way catalyst would reduce the emissions of NOX,PM,HC and CO for now, thus the new types of catalyst for diesel engine exhaust purification is urgently needed to be developed.The perovskite-type complex oxide samples, LaCoO3 ((?)=1mol,1.5mol,2mol,3mol,3.5mol), LaFeO3 ((?)=1mol,2mol,3mol,3.5mol), were prepared by the self-combustion method. The samples were characterized by means of XRD,BET,SEM. The main conclusions are summarized as follows:1,Among preparing methods to produce perovskite-type catalysts, the self-combustion method for producing the perovskite-type catalyst has its unique advantages, so as high purity, few impurity, simple operation, excellent physical properties, high specific surface area and pore. Therefore, it can quicken the basic research on both the primary selection and the formula of catalysts, and make the research more efficient.2,Both of La0.9K0.1CoO3 and La0.9K0.1FeO3 catalyst have their own advantages. La0.9K0.1FeO3 can provide the higher catalytic reaction of places because of specific surface area of La0.9K0.1FeO3 is greater than La0.9K0.1CoO3; La0.9K0.1CoO3 can improve reaction rate for its higher pore. The paper chose the match ratios of (?)=lmol LaCoO3 and (?)=3.5mol LaFeO3 as ideal samples in numerous formula of catalysts.The paper is ueing the device of testing catalyst samples for preparations to evaluate their performance. The main conclusions are summarized as follows:3,The catalyst of La0.9K0.1CoO3 can slightly improve to remove NOX and PM by self-combustion, and its conversion can reach to 24% with excellent catalytic properties. But, La0.9K0.1CoO3 has higher ignition temperature 290℃than 270℃of La0.9K01.FeO3, and the PM conversion of La0.9K0.1CoO3 is not good as La0.9K0.1FeO3. The mixture catalyst can not adjust best temperture, so purification rate is not good just 16%.4,Both two kinds of catalysts have higher purification ratio in general conditions than the richer mixture conditions, and have lower ignition temperature. It can remove NOx and PM with higher catalytic properties in general conditions.