以不同温度焙烧得到的Zr0.5Al0.5O1.75复合氧化物为载体,制备了系列1.5%Pd/Zr0.5Al0.5O1.75催化剂样品.采用N2吸附-脱附、X射线衍射、H2程序升温还原、O2程序升温脱附及CO化学吸附等手段对催化剂进行了表征,并测试了催化剂在模拟稀燃天然气汽车尾气中的活性和抗H2O中毒性能.结果表明,载体焙烧温度对催化剂活性的影响很大,其中以950℃焙烧时催化剂的活性最高.在不含H2O条件下,该催化剂对甲烷的起燃温度(T50)和完全转化温度(T90)分别为274和315℃;而在含H2O条件下的T50和T90分别为325和356℃,表现出较高的低温活性和优良的抗H2O中毒能力.%The Zr0.5Al0.5O1.75 mixed oxide was prepared by coprecipitation method. and calcined at different temperatures and then used as a support to prepare a 1.5％ Pd/Zr0.5Al0.5O1.75 catalyst. The catalyst activity and H2O resisting properties were evaluated in a mixed gas that simulated the exhaust of lean-burn natural gas fuelled vehicles (lean-burn NGVs). The catalyst was further characterized by N2 adsorption-desorption, X-ray diffraction, H2 temperature-programmed reduction, O2 temperature-programmed desorption and CO chemisorption. It was found that the catalyst activity was greatly influenced by the calcination temperature of the Zr0.5Al0.5O1.75 support. For the catalyst with the support calcined at 950 ℃. the light-off temperature (T50) and complete conversion temperature (T90) of methane in the absence of H20 were 274 and 3 15 ℃, respectively. In the presence of H20, T50 and T90 were 325 and 356 ℃, respectively. The results indicated that the catalyst had higher catalytic activity at low temperature and higher capability to resist H2O poisoning.
展开▼
