负载型Pd三效催化剂:载体CeO_2-ZrO_2-BaO的制备及催化性能(英文)

Pd Supported Three-Way Catalyst:Preparation of CeO_2-ZrO_2-BaO Support and Catalytic Performance

制备了不同BaO含量的CeO2-ZrO2储氧材料,并以此材料为载体浸渍H2PdCl6制得三效催化剂。结果表明,不论新鲜还是1000℃老化状态下,以10%BaO添加CeO2-ZrO2储氧材料制备的Pd三效催化剂活性最佳,起燃和完全转化温度最低。XPS结果证实,10%BaO添加,通过稳定PdO活性组分并改变其电子环境使得催化剂有最佳活性。而随着BaO含量持续增加,Pd活性组分相对处于较氧化状态。储氧量、低温N2吸附-脱附测试以及XRD测试结果均表明10%BaO添加的材料储氧量,比表面积以及孔容均最大,而且有适应三效催化的孔径。这些结果均有助于以其制备的Pd三效催化剂获得更好的活性以及热稳定性。

The three-way catalysts were prepared by impregnating BaO doped CeO2-ZrO2 solid solutions with H2PdCl6. The results show that Pd catalyst prepared by the support with 10wt% BaO has the best activity and the lowest light-off temperature both before and after aging at 1 000 ℃ for 5 h. The XPS results confirm that a doping of 10% BaO can improve the catalytic activity by stabilizing the active phase of PdO and changing the electronic environment of the active phase of Pd. With more doped BaO, Pd will be at lower oxidation state. The oxygen storage capacity（OSC）, low temperature nitrogen adsorption-desorption and XRD tests of the supports show that the support material containing 10% BaO has the largest specific area and pore volume, proper pore diameter and the highest OSC, which can improve the catalytic performance and the thermal stability of Pd three-way catalysts.