催化学报

催化学报 ›› 2012, Vol. 33 ›› Issue (6): 1020-1026.DOI: 10.3724/SP.J.1088.2012.11237

• 研究论文 • 上一篇    下一篇

整体式 Pd/La2O3-Al2O3 和 Pd/CeO2-ZrO2-Y2O3 催化剂上汽油车尾气净化性能的比较

崔亚娟, 何胜楠, 方瑞梅, 史忠华*, 龚茂初, 陈耀强   

  1. 四川大学化学学院, 绿色化学与技术教育部重点实验室, 四川成都 610064
  • 收稿日期:2011-12-16 修回日期:2012-02-15 出版日期:2012-05-30 发布日期:2012-05-30

Comparison of Automotive Exhaust Purification Performance of Monolith Catalysts Pd/La2O3-Al2O3 and Pd/CeO2-ZrO2-Y2O3

CUI Yajuan, HE Shengnan, FANG Ruimei, SHI Zhonghua*, GONG Maochu, CHEN Yaoqiang   

  1. Key Laboratory of Green Chemistry & Technology of Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, Sichuan, China
  • Received:2011-12-16 Revised:2012-02-15 Online:2012-05-30 Published:2012-05-30

PDF

863

摘要： 采用共沉淀法制备了耐高温高比表面积的La2O3-Al2O3(LA) 材料和 CeO2-ZrO2-Y2O3 (CZY) 储氧材料, 并用浸渍法制备了整体式 Pd/LA 和 Pd/CZY 汽油车尾气净化三效催化剂, 考察了它们的三效催化性能和空燃比性能, 并单独通过水煤气变换和 CO 氧化反应性能的考察, 探讨了两种催化剂空燃比窗口扩大的原因. 结果表明, Pd/CZY 催化剂三效窗口明显较宽, 且催化氧化 CO 的性能明显更优; 对于 CO + NO 反应, Pd/CZY 催化剂的活性较高. 当反应中逐步通入 O2 后, 抑制了该反应的进行, 但 CO 氧化的转化率升高, 而 NO 转化率降低, 直至 CO + NO 反应完全被抑制, 表明 CO 氧化反应对于抑制催化剂在 NO 贫燃方向的窗口具有一定的作用. 另外, Pd/CZY 催化剂上对于水煤气变换反应性能明显优于 Pd/LA 催化剂, 在一定温度下逐步通入 O2 后, 不会抑制水煤气变换反应的发生; 当逐步通入 NO 时, 可以促进水煤气变换反应的进行, 表明 Pd/CZY 催化剂在富燃时对扩展 CO 转化窗口的性能明显优于 Pd/LA 催化剂.

关键词: 储氧材料, 耐高温材料, 三效催化剂, 水煤气变换, 一氧化碳, 氧化反应, 氮氧化物

Abstract: Two kinds of support materials, the thermal-stability material La2O3-Al2O3 (LA) and oxygen storage material CeO2-ZrO2-Y2O3 (CZY), were prepared by co-precipitation. Pd/LA and Pd/CZY catalysts were prepared by impregnation and they were further fabricated as three-way catalysts in a monolith form. The Pd/LA and Pd/CZY three-way catalysts thus prepared were evaluated with a simulated automobile exhaust in terms of the relationships of three way performance with the air-to-fuel ratio (A/F) window and with temperatures. The results indicated that the A/F window and the three-way activity of the Pd/CZY catalyst were broader and higher than those of the Pd/LA catalyst. To investigate in more details, several reactions that involved CO in exhaust purification process such as CO oxidation, water-gas shift (WGS) reaction, and NO reduction by CO were examined over Pd/LA and Pd/CZY catalysts. These preliminary studies revealed that the advantages of the Pd/CZY catalyst is mainly from the unique properties of the CeO2 oxygen storage material. Furthermore, it was found that addition of either O2 or NO in reactant gases are favorable for the WGS reaction, which gives some clues for developing an advanced three-way purification process.

Key words: oxygen storage material, thermal-stability material, three-way catalyst, water-gas shift, carbon monoxide, oxidization, nitrogen oxide