Acta Phys. -Chim. Sin. ›› 2015, Vol. 31 ›› Issue (9): 1771-1779.doi: 10.3866/PKU.WHXB201507141

• CATALYSIS AND SURFACE SCIENCE • Previous Articles     Next Articles

Effects of Zr Addition on the Performance of the Pd-Pt/Al2O3 Catalyst for Lean-Burn Natural Gas Vehicle Exhaust Purification

Wei. HU1,Yun. WANG1,Hong-Yan. SHANG1,Hai-Di. XU2,3,Lin. ZHONG1(),Jian-Jun. CHEN2,Mao-Chu. GONG2,Yao-Qiang. CHEN1,2,3()   

  1. 1 College of Chemical Engineering, Sichuan University, Chengdu 610064, P. R. China
    2 Institute of New Energy and Low-Carbon Technology, Sichuan University, Chengdu 610064, P. R. China
    3 Key Laboratory of Green Chemistry & Technology of Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, P. R. China
  • Received:2015-05-04 Published:2015-09-06
  • Supported by:
    the National Natural Science Foundation of China(21173153);Project from Sichuan Provincial Environment Office,China(2011HB002);Science and Technology Support Project of Science and Technology Department of Sichuan Province, China(2012FZ0008)

Abstract:

The catalytic activity, hydrothermal aging resistance, and sulfur tolerance of a Pd-Pt-based methane oxidation catalyst were evaluated in a fixed fluidized bed reactor containing simulated lean-burn natural gas vehicle exhaust gases. Zirconium-doped Pd-Pt/Al2O3 (Pd-Pt/ZrxAl(1-x)O(3+x)/2) was found to significantly improve the catalytic activity, hydrothermal aging resistance, and sulfur tolerance. Zr-modified alumina supports were prepared by co-precipitation with molar ratios of Zr to Al of 0 : 1, 0.25 : 0.75, 0.5 : 0.5, 0.75 : 0.25, and 1 : 0. The Pd-Pt bimetallic catalysts containing 1.5% (w, mass fraction) Pd and 0.3% (w) Pt supported on the above-modified composite supports were prepared by the co-impregnating method. The catalysts were characterized by N2 adsorption/desorption, X-ray diffraction(XRD), H2 temperatureprogrammed reduction (H2-TPR), O2 temperature-programmed desorption, and X-ray photoelectron spectroscopy (XPS). The results show that the crystallinity of the samples, dispersion of the active component, number of Pd2+ species, and electron density around Pd2+ species increase after addition of ZrO2 to Al2O3 supports. Compared with the activity results of Pd-Pt/Al2O3 and Pd-Pt/ZrO2 catalysts after different pretreatment conditions, the performance of the catalyst is greatly enhanced by adding ZrO2 in the Al2O3 supports, and Pd-Pt/Zr0.5Al0.5O1.75 shows the best catalytic activity, strongest hydrothermal aging resistance, and highest sulfur tolerance among the investigated catalysts.

Key words: Aluminum, Zirconium, Different molar ratios, Support, Natural gas fuelled vehicle, Catalytic performance

MSC2000: 

  • O643