Acta Phys. -Chim. Sin. ›› 2014, Vol. 30 ›› Issue (6): 1187-1193.doi: 10.3866/PKU.WHXB201404281

• CATALYSIS AND SURFACE SCIENCE • Previous Articles     Next Articles

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).

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