Chem. J. Chinese Universities ›› 2004, Vol. 25 ›› Issue (9): 1679.

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Structural Characterization and Catalytic Properties of Three-way Catalyst La 1-xCexFe 1-y-nCoyRunO3

LI Li1,2, YUAN Fu-Long2,3, FU Hong-Gang2, GUANG Huan-Zhu2, ZHANG Guo2, JIANG An-Xi1   

  1. 1. School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China;
    2. School of Chemistry and Material Sciences, Heilongjiang University, Harbin 150080, China;
    3. School of Mechanical and Electrical Engineering, Harbin Institute of Technology, Harbin 150001, China
  • Received:2004-01-29 Online:2004-09-24 Published:2004-09-24

Abstract: The La1-xCexFe1-y-nCoyRunO3(x,y=0.1-0.5, n=0.01-0.1) were synthesized by sol-gel method. The phase structures of the compounds do not change with Ru being doped, but 2θ decreases and crystal cell parameters increase determined by employing XRD technique. IR analysis show that the position and shape of adsorption peaks are almost the same in all compounds, except for the 600 cm-1 peaks stretching to a high frequency and are changed in disorder with Ru content increasing. Comparing to unsubstituted samples, the band of sample with n=0.01 stretching to a higher region was observed with Ru being introduced into the compound, and the max adsorption peaks emerged in ν 1 when n=0.05, but the strength of peaks in ν 2 was very weak. The enhanced bond strength of Fe-O and Co-O could be attributed to the coordinative effect of Fe-O-Ru and Fe-O-Co, and also the deformation of Fe-O-Co structures. XPS testifies that Fe elements have many valences as the charge densities arise in the out layer. Ce combines with multihydroxy but not oxygen in the surface layer, meanwhile, the content of other oxygen species increased and catalytic activities improved. O2-TPD results show that the temperature of adsorption oxygen and lattice oxygen decreased and the content of vacancy of oxygen increased. The catalytic activities are improved which is related to the A ion vacancies when x(Ce)≤0.2. H2-TPR is in accordance with TPD in the result. The catalytic activities are improved which is related to the A ion vacancies and the enhancing lattice oxygen activities, and La0.8Ce0.2Fe0.7Co0.2Ru0.1O3 is the best one among all catalysts mentioned above.

Key words: Three-way catalyst, Structural characterization, Catalytic purification

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