B位元素掺杂对La_(0.8)Ce_(0.2)Mn_xM_(1-x)O_3/γ-Al_2O_3催化剂催化VOCs燃烧性能的影响

Effect of Element Doping in the B Cation Site of La_(0.8)Ce_(0.2)Mn_xM_(1-x)O_3/γ-Al_2O_3 on Its Catalytic Activity of VOCs Combustion

以γ-Al2O3为载体,采用等体积浸渍法制备负载型钙钛矿催化剂La0.8Ce0.2Mnx M1-x O3/γ-Al2O3,考察了B位元素类型和B位元素配比对其催化甲苯燃烧性能的影响,并考察了其对"三苯系"挥发性有机化合物(VOCs)的催化燃烧性能,同时对催化剂进行XRD、BET和SEM表征分析。结果表明,催化剂的最佳形式为La0.8Ce0.2Mn0.8Co0.2O3/γ-Al2O3,在该催化剂作用下甲苯的起燃温度T50和完全转化温度T90分别为243和303℃;就"三苯系"单组分燃烧反应而言,催化剂对二甲苯燃烧的催化活性最高,对苯燃烧的催化活性最低,对"三苯系"混合物燃烧也表现出了良好的催化效果。负载型钙钛矿催化剂保持了完整的钙钛矿结构,负载后催化剂的比表面积和孔隙率都大大增加,自身得以更大程度地分散,整体呈蓬松的絮状,更有利于催化剂的实际应用。

La0.8Ce0.2MnxM1-xO3 was coated on γ-Al2O3 by equal volume impregnation method.The catalytic combustion of toluene over the obtained La0.8Ce0.2MnxM1-xO3/γ-Al2O3 catalyst with different element type and element ratio in B cation site was tested,as well as benzene series of volatile organic compounds （VOCs）.The catalysts were characterized by XRD,BET and SEM.The results showed that the optimum composition of the catalyst for catalytic combustion of VOCs was La0.8Ce0.2Mn0.8Co0.2O3/γ-Al2O3.Catalyzed by this catalyst,the ignition temperature T50 and complete conversion temperature T90 of toluene combustion were 243 and 303℃,respectively.For the combustion of separate compound of benzene series of VOCs,La0.8Ce0.2Mn0.8Co0.2O3/γ-Al2O3had the highest catalytic activity to xylene and the lowest activity to benzene.La0.8Ce0.2Mn0.8Co0.2O3/γ-Al2O3 also showed high catalytic activity to the combustion of benzene series VOCs mixture.The supported perovskite catalyst La0.8Ce0.2MnxM1-xO3/γ-Al2O3 maintained perfect perovskite structure and dispersed uniformly with its surface area and porosity greatly increased and fluffy flocculent,which was conductive to practical application.