NO催化氧化催化剂的制备与性能研究

以柠檬酸为络合剂,采用溶胶-凝胶法制备了Ce—Co—Mn—O复合氧化物催化剂,研究了催化剂的钴锰比、Ce含量、焙烧温度对NO催化氧化转化率的影响。当Ce、Co、Mn物质的量的比为2：1：3、450℃焙烧时,催化剂的NO转化率最高可达72％,而在其他条件下催化剂活性较差。催化剂样品的XRD、BET及SEM—EDAX分析显示：焙烧温度≤450℃的催化剂呈现出无定形态、大量孔隙通道及较大比表面积,当焙烧温度升高至600℃,开始出现晶相分离,而当焙烧温度为750℃时,催化剂的表面伴生出尖晶石相,导致其活性急剧降低。

Study on Preparation and Performance of NO Catalytic Oxidation Catalyst

Taking citric acid as complexing agent, the Ce-Co-Mn-O compound oxide catalyst is prepared by sol-gel method. The influence of cobalt/manganese ratio of the catalyst, Ce content and calcination temperature on NO catalytic oxidation conversion rate is studied. Under the Ce/Co/Mn molar ratio of 2 ： 1 ： 3 and calcinations at 450 ℃, the maximum NO conversion rate of the catalyst can reach 73% , however, the catalyst has a poor activity under the other conditions. XRD, BET and SEM-EDAX analyses of the samples show that when the calcinations temperature is equal to or less than 450 ℃, the catalyst has an amorphous state, a large number of pore channels and a large specific surface area. The crystalline phase separation occurs at 600℃, and the spinel phase occurs on the catalysts surface at 750℃, which leads to a drastic reduction of the activity.