催化学报 ›› 2012, Vol. 33 ›› Issue (11): 1762-1771.DOI: 10.1016/S1872-2067(11)60445-2

• 研究论文 • 上一篇    下一篇

不同锆源对 Pd/Ce0.45Zr0.45La0.1O1.95 整体式三效催化剂性能的影响

陈山虎1, 姚艳玲2, 兰丽1, 曹毅1, 闫朝阳1, 龚茂初1, 陈耀强1,?   

  1. 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; 2惠州学院化学工程系, 广东惠州 516007
  • 收稿日期:2012-07-07 修回日期:2012-08-20 出版日期:2012-11-16 发布日期:2012-11-16

Effect of Zirconium Precursor on Performance of Pd/Ce0.45Zr0.45La0.1O1.95 Three-Way Catalyst

CHEN Shanhu1, YAO Yanling2, LAN Li1, CAO Yi1, YAN Chaoyang1, GONG Maochu1, CHEN Yaoqiang1,?   

  1. 1Key Laboratory of Green Chemistry and Technology of the Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, Sichuan, China; 2Department of Chemical Engineering, Huizhou University, Huizhou 516007, Guangdong, China
  • Received:2012-07-07 Revised:2012-08-20 Online:2012-11-16 Published:2012-11-16

摘要: 分别以 ZrOCO3, ZrO(NO3)2 和 Zr(NO3)4 为锆源采用双氧水氧化-共沉淀法合成了 Ce0.45Zr0.45La0.1O1.95 储氧材料, 并用湿法浸渍法制备了 Pd/Ce0.45Zr0.45La0.1O1.95 三效催化剂, 用 X 射线衍射、拉曼光谱、N2 吸附、X 射线光电子能谱、氢气程序升温还原和氧脉冲等技术对该催化剂进行了表征. 结果表明, 以 ZrOCO3 和 ZrO(NO3)2 为锆源时所制催化剂上只能检测到单一的 CeO2-ZrO2 立方相, 而以 Zr(NO3)4 为锆源制备的催化剂经老化后却能检测到四方相; 另外, 在模拟汽车尾气组分和工作条件下考察了整体型 Pd/Ce0.45Zr0.45La0.1O1.9 催化剂的三效活性. 结果表明, 以 ZrOCO3 为前驱体制备的整体式 Pd/Ce0.45Zr0.45La0.1O1.9 催化剂对 C3H8, CO 和 NO 具有最佳的催化活性. 认为 ZrOCO3 更有利于 Zr4+ 和 La3+进入 CeO2 晶格形成均一固溶体, 从而提高催化剂的高温稳定性和氧化还原性能.

关键词: 储氧材料, 氧化共沉淀, 热稳定性, 氧化还原性能, 三效活性

Abstract: Three types of Ce0.45Zr0.45La0.1O1.95 mixed oxides were prepared by H2O2-assisted precipitation using ZrOCO3, ZrO(NO3)2, and Zr(NO3)4 as precursors. The Pd/Ce0.45Zr0.45La0.1O1.95 three-way catalysts were prepared by the wet impregnation and characterized by the X-ray diffraction (XRD), Raman spectroscopy, nitrogen adsorption, X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR), and oxygen storage capacity. XRD and Raman spectroscopy results showed that the use of ZrOCO3 or ZrO(NO3)2 gave a CeO2-ZrO2 mixed oxide with a cubic phase of high thermal stability, while an extra t″-phase was observed in the aged Pd/Ce0.45Zr0.45La0.1O1.95 catalyst prepared using Zr(NO3)4. The activities of the three catalysts were evaluated using simulated exhaust gas under working conditions. The Pd/Ce0.45Zr0.45La0.1O1.95 catalyst prepared using ZrOCO3 as precursor gave the best activities for C3H8, CO, and NO conversion. The use of ZrOCO3 as precursor was better suited for the formation of Ce3+ and more favorable for the homogeneous insertion of Zr4+ and La3+ into the CeO2 lattice, which resulted in better thermal stability and enhanced redox properties of the Pd/Ce0.45Zr0.45La0.1O1.95 catalyst.

Key words: oxygen storage material, oxidation-coprecipitation, thermal stability, redox property, three-way activity