负载型La2-xSrxCoO4类钙钛矿复合氧化物CO催化氧化性能

摘要

MgA1204-supported La2-xSrx CoO4 ( x = 0.2,0.4,0.6 and 0.8 ) mixed oxide catalysts were prepared by citric acid complex-impregnation method and characterized by XRD, H2-TPR and BET. The catalytic performance of the catalysts for CO oxidation was tested in a fixed-bed microreactor. XRD results showed that active component La2-xSrxCoO4 could formed A2BO4 perovskite-like structure on MgAl2O4 support when x =0.2,0.4,0.6 and 0.8. H2-TPR results indicated that the activity of surface and lattice oxygen species was enhanced with the increase of x from 0.2 to 0.8. The catalytic activity tests showed that the catalyst with x = 0.8 exhibited the best catalytic activity for CO oxidation and CO conversion reached 100％ at 400 ℃. Water vapour had little influence on the catalytic activity. The activity of the catalysts was obviously decreased with the exposure of the catalysts to SO2 atmosphere.%采用柠檬酸络合-浸渍法制备了以镁铝尖晶石MgAl2O4为载体、复合氧化物La2-xSrxCoO4(X=0.2、0.4、0.6和0.8)为活性组分的催化剂,通过XRD、H2-TPR和BET等分析方法对催化剂进行表征,利用固定床微型反应器测试催化剂对CO氧化的催化性能,并考察水蒸汽和SO2对其活性的影响.结果表明,X=0.2、0.4、0.6和0.8时,活性组分La2-xSrxCoO4均能在镁铝尖晶石MgAl2O4载体上形成类钙钛矿A2BO4结构;随着X增大,催化剂化学吸附氧和晶格氧的活动性增强,有利于CO催化氧化.活性测试结果表明,x=0.8,催化剂对CO氧化的催化活性最佳,400℃CO转化率可达100%;水蒸汽对催化剂活性的影响较小,SO2显著降低催化剂的催化活性.