Promoter of (Ce-Zr)O2 Solid Solution Modified by Praseodymia in Three-Way Catalysts
来源期刊：JOURNAL OF RARE EARTHS2003年第4期
论文作者：刘涛 胡天斗 林培琰 孟明 谢亚宁 汪文栋 伏义路
Key words：catalytic chemistry; praseodymium; (Ce-Zr)O2 solid solution; three-way catalysts; rare earths;
Abstract: The three-way catalysts (TWCs) promoters (Ce-Zr)O2, (Pr-Ce-Zr)O2 and (Pr-Zr)O2 were prepared by sol-gel like method. They were characterized by XRD, EXAFS and BET surface area determination. The reduction features of the promoters were measured by temperature-programmed reduction (TPR) of H2 to access the potential for the promoters containing praseodymia as oxygen storage component in three-way catalyst. The (Pr-Zr)O2 cubic solid solution is formed at high temperature up to 800 ℃, which makes it more reducible than the (Ce-Zr)O2 solid solution. For the (Pr-Ce-Zr)O2 samples, the ternary solid solution plays an important role in the reduction process. The performance of the three-way catalysts with fully formulated Pt, Pd and Rh is proceeded by using both light-off temperature under a stoichiometric gas composition and the conversion of CO, C3H6 and NO under changing air/fuel ratio at a constant reaction temperature 400 ℃. The results indicate that a small amount of praseodymia doping into (Ce-Zr)O2 favors the light-off temperature of C3H6 and NO, and all the catalysts containing praseodymia obviously exhibits enhanced width of S value for NO conversion at lean region (S≥1.00).
刘涛1，胡天斗1，林培琰2，孟明2，谢亚宁1，汪文栋2，伏义路2
(1.Beijing Synchrotron Radiation Facility, Beijing 100039, China;
2.Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China)
Abstract:The three-way catalysts (TWCs) promoters (Ce-Zr)O2, (Pr-Ce-Zr)O2 and (Pr-Zr)O2 were prepared by sol-gel like method. They were characterized by XRD, EXAFS and BET surface area determination. The reduction features of the promoters were measured by temperature-programmed reduction (TPR) of H2 to access the potential for the promoters containing praseodymia as oxygen storage component in three-way catalyst. The (Pr-Zr)O2 cubic solid solution is formed at high temperature up to 800 ℃, which makes it more reducible than the (Ce-Zr)O2 solid solution. For the (Pr-Ce-Zr)O2 samples, the ternary solid solution plays an important role in the reduction process. The performance of the three-way catalysts with fully formulated Pt, Pd and Rh is proceeded by using both light-off temperature under a stoichiometric gas composition and the conversion of CO, C3H6 and NO under changing air/fuel ratio at a constant reaction temperature 400 ℃. The results indicate that a small amount of praseodymia doping into (Ce-Zr)O2 favors the light-off temperature of C3H6 and NO, and all the catalysts containing praseodymia obviously exhibits enhanced width of S value for NO conversion at lean region (S≥1.00).
Key words:catalytic chemistry; praseodymium; (Ce-Zr)O2 solid solution; three-way catalysts; rare earths;
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