结构型LaMnO_3钙钛矿催化剂的催化燃烧活性和热稳定性

Activity and thermal stability of LaMnO_3 monolithic catalysts for catalytic combustion of toluene

为降低堇青石载体对钙钛矿催化剂活性和稳定性的影响,以堇青石蜂窝陶瓷为基材,采用原位沉淀和悬浮浸渍技术分别制备了SiO2和La2O3为涂层的结构型LaMnO3催化剂,通过甲苯催化燃烧反应考察了催化剂的活性和热稳定性。结果表明,原位沉淀技术虽然可以均匀和高强度地在载体表面负载La、Mn活性组分,但无法在表面形成LaMnO3钙钛矿的活性相。悬浮浸渍技术则可以保持LaMnO3催化剂的结构和活性,结构催化剂与粉末LaMnO3表现出相似的活性规律。La2O3涂层比SiO2涂层可以更有效地保持LaMnO3在蜂窝陶瓷载体表面的高活性和热稳定性。

To reduce the effect of cordierite carrier on the activity and thermal stability of perovskites,LaMnO3 monolithic catalysts with La2O3 and SiO2 coating were prepared by in-situ deposition and slurry impregnation.The activity and thermal stability of the catalysts were investigated in catalytic combustion of toluene.It was shown that La and Mn oxides could be deposited uniformly and firmly on the surface of cordierite,but the active phases of LaMnO3 perovskites could not be formed by in-situ deposition.However the progress of slurry impregnation could maintain the structure and activity of LaMnO3 catalyst.The monolithic LaMnO3 showed the same catalytic performance as the pure LaMnO3 powder catalyst.La2O3 coating was more effective than SiO2 coating to keep high thermal stability and activity of LaMnO3 on the surface of cordierite.