单钯型汽车尾气净化催化剂的催化活性研究

Catalytic activity of palladium-only catalyst for automobile exhaust purification

分别采用浸渍-还原和化学镀工艺制备了新型单钯汽车尾气净化催化剂,研究Pd负载量和制备工艺对CO、HC、NO 3种汽车尾气成分转化率、起燃温度的影响,并研究了催化剂的抗老化性能。结果表明:Pd的最佳负载量为2 g/L,此时3种气体在400℃时的转化率均在90%以上;采用化学镀工艺制备的催化剂活性优于浸渍-还原工艺制备的催化剂;单钯型催化剂对CO氧化有比较好的选择性,要通过改进助剂成分,或者在单Pd配方的基础上添加少量的Pt或者Rh,以增强催化剂对NO和HC的抗老化性能。

A new palladium-only catalyst for automobile exhaust purification was prepared by dipping-reduction and chemical plating process respectively. The impact of palladium loading and the preparation process on the ignition temperature and conversion rate of three vehicle exhaust composition of CO, HC and NO was discussed. Also the anti-aging properties of the catalyst were studied. The results show that the conversion rate of the three exhaust at 400 ℃ is more than 90% when 2 g/L of palladium is loaded; the catalyst activity from chemical plating process is better than that from the dipping-reduction process ; the palladium-only catalyst is in good selectivity for CO oxidation, the anti-aging properties of catalysts for NO and HC can be enhanced by improving additives ingredients, or by adding a small amount of Pt or Rh on the basis of palladium-only formula.