Effects of co-precipitation temperature on structure andproperties of La and Ydopedcerium zirconium mixed oxides
(1. National Engineering Research Center for Rare Earth,GRINM Group Co., Ltd., Beijing 100088, China;
2. General Research Institute for Nonferrous Metals, Beijing 100088, China;
3. GRIREM Advanced Materials Co., Ltd., Beijing 100088, China;
4. GRIREM Hi-Tech Co., Ltd., Langfang 065201, China)
2. General Research Institute for Nonferrous Metals, Beijing 100088, China;
3. GRIREM Advanced Materials Co., Ltd., Beijing 100088, China;
4. GRIREM Hi-Tech Co., Ltd., Langfang 065201, China)
Abstract: Due to the oxygen storage and release properties, cerium zirconium mixed oxides are recognized as the key material in automotive three-way catalysts. To reveal the effects of co-precipitation temperature on structure, physical and chemical properties of multi-doped cerium zirconium mixed oxides, a series of La and Ydoped cerium zirconium mixed oxides (CZLYs) were synthesized via a co-precipitation method, and the physical and chemical properties of CZLYs were systemically characterized by XRD, N2 adsorption-desorption, TEM, XPS, oxygen storage capacity (OSC) and hydrogen temperature programmed reduction (H2-TPR). The results show that co-precipitation temperature is an important parameter to influence the crystal size, oxygen storage capacity and thermal stability of CZLYs. When the co-precipitation temperature was 60°C, the best redox properties and thermal stability of CZLYs were obtained.After thermal treatment at 1100°C for 10 h, the specific surface area and oxygen storage capacity of the corresponding aged sample were 15.42 m2/g and 497.7 μmol/g, respectively. In addition, a mechanism was proposed to reveal the effects of co-precipitation temperature on the structure and properties of CZLYs.
Key words: La and Ydoping; cerium zirconium mixed oxides; co-precipitation temperature; crystal size; thermal stability