物理化学学报 >> 2014, Vol. 30 >> Issue (6): 1187-1193.doi: 10.3866/PKU.WHXB201404281

催化和表面科学 上一篇    下一篇

表面覆盖SiO2用于提高Pt-Pd/CeO2-ZrO2-Al2O3商用柴油机氧化型催化剂的抗硫性

杨铮铮1, 杨怡2, 赵明2, 龚茂初2, 陈耀强1,2   

  1. 1 四川大学建筑与环境学院, 成都610064;
    2 四川大学化学学院, 绿色化学与技术教育部重点实验室, 成都610064
  • 收稿日期:2014-03-17 修回日期:2014-04-28 发布日期:2014-05-26
  • 通讯作者: 陈耀强 E-mail:nic7501@scu.edu.cn
  • 基金资助:

    国家自然科学基金(21173153),国家高技术研究发展计划项目(863)(2013AA065304)及四川省科技厅科技支撑项目(2011GZ0035,2012FZ0008)资助

Enhanced Sulfur Resistance of Pt-Pd/CeO2-ZrO2-Al2O3 Commercial Diesel Oxidation Catalyst by SiO2 Surface Cladding

YANG Zheng-Zheng1, YANG Yi2, ZHAO Ming2, GONG Mao-Chu2, CHEN Yao-Qiang1,2   

  1. 1 College of Architecture and Environment, Sichuan University, Chengdu 610064, P. R. China;
    2 Key Laboratory of Green Chemistry & Technology of the Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, P. R. China
  • Received:2014-03-17 Revised:2014-04-28 Published:2014-05-26
  • Contact: CHEN Yao-Qiang E-mail:nic7501@scu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21173153), National High-Tech Research and Development Program of China (863) (2013AA065304), and Major Research Program of Science and Technology Department of Sichuan Province, China (2011GZ0035, 2012FZ0008).

摘要:

向Pt-Pd/CeO2-ZrO2-Al2O3 (Pt-Pd/CZA)商用柴油机氧化型催化剂(DOC)中加入多孔SiO2以提高其抗硫性. 使用多层涂覆法在Pt-Pd/CZA 催化剂表面覆盖一层多孔SiO2,从而制得SiO2/Pt-Pd/CeO2-ZrO2-Al2O3(SiO2/Pt-Pd/CZA)抗硫DOC. 并使用扫描电子显微镜(SEM),H2程序升温还原(H2-TPR),氮气吸脱附,X射线能谱(EDX)和热重分析(TGA)等对其进行表征. SEM结果显示,SiO2层以多孔形式均匀覆盖在催化剂表面. 氮气吸脱附结果表明,所添加的SiO2的织构性质与Pt-Pd/CZA 催化剂的织构性质相似,因而表面覆盖的SiO2并未明显改变Pt-Pd/CZA催化剂的比表面积和孔结构. H2-TPR结果证实表面覆盖的SiO2不影响Pt-Pd/CZA催化剂的还原性能. EDX和TGA结果说明表面覆盖SiO2可以抑制硫物种在催化剂表面的形成及累积. 最终,本文所制备的SiO2/Pt-Pd/CZA催化剂在保持Pt-Pd/CZA商用DOC的高活性及耐久性的同时有效提高了其抗硫性.

关键词: 柴油机氧化型催化剂, 抗硫性, 整体式催化剂, 多层涂覆, 机动车尾气

Abstract:

In this work, porous SiO2 was added to the Pt-Pd/CeO2-ZrO2-Al2O3 (Pt-Pd/CZA) commercial diesel oxidation catalyst (DOC) to improve its sulfur resistibility. The SiO2/Pt-Pd/CeO2-ZrO2-Al2O3 (SiO2/Pt-Pd/CZA) catalyst was prepared by surface coating porous SiO2 onto the Pt-Pd/CZAmonolithic commercial DOC using a multilayer coating method. The as-prepared catalysts were characterized by scanning electron microscopy (SEM), H2 temperature-programmed reduction (H2-TPR), nitrogen adsorption-desorption, energy-dispersive X-ray (EDX) spectroscopy, and thermogravimetric analysis (TGA). SEM images show that the SiO2 layer is porous and uniformly covers the surface of the catalyst. Nitrogen adsorption-desorption isotherm results imply that the texture properties of the as-added SiO2 are similar to those of the Pt-Pd/CZA catalyst, and hence the specific surface area and pore structure of the Pt-Pd/CZA catalyst do not obviously change upon cladding with SiO2. The H2-TPR results imply that the reduction property of the Pt-Pd/CZA catalyst is not obviously affected by surface cladding with SiO2. EDX spectroscopy and TGA results demonstrate that the formation and accumulation of sulfur-contained species on the Pt-Pd/CZA catalyst are suppressed by the SiO2 surface coating. Finally, the as-prepared SiO2/Pt-Pd/CZA catalyst efficiently retained its high catalytic performance and improved the sulfur resistance of the Pt-Pd/CZA commercial DOC.

Key words: Diesel oxidation catalyst, Sulfur resistance, Monolithic catalyst, Multilayer coating, Vehicle exhaust

MSC2000: 

  • O643