尿素基水热共沉淀法铈锆固溶体的制备及应用

Preparation of Ceria-Zirconia Solid Solution by Urea-Based Hydrothermal-Copricipitation Method and its Catalytic Application

采用水热共沉淀法制备了一系列铈锆固溶体CexZr1-xO2,用XRD,BET,TEM,H2-TPR等对其晶相结构、表面形貌,热稳定性等进行了研究。结果表明,所制备的铈锆固溶体经550焙烧4 h后,在x=1．0-0．2的范围内均呈单一晶相结构;经过900℃老化6 h之后仍然结构保持稳定。其中Ce0．70Zr0.30O2比例的固溶体经过550℃,4 h和900℃,6 h焙烧后表面积分别为133．1和21．1 m2·g-1。试验同时对以样品 Ce0.70Zr0．30O2为涂层材料制备的LPG三效催化剂催化性能进行了研究,3种气体CO,HC和NO的起燃温度分别为244．6,286．9和250．0℃, 空燃比操作窗口λ范围为0.84-1．04,表明催化剂具有较好起燃特性及较宽的空燃比操作窗口。

A series of CexZr1-xO2 solid solutions were prepared by urea-based hydrolysis-eoprecipitation method. The samples were charact-erized by BET, XRD, SEM, and H2-TPR. The results show that CexZr1-xO2 prepared owns single phase after calcinations at 550 or 900 ℃ when CeO2 ratio is in the range of 1.0 - 0.2. The solid solution prepared show large surface area, good thermal stability, and high redox capacity. The surface area of Ce0.70Zr0.30O2 calcined could reach 133.1 m2·g-1 after cailcination at 550 ℃ for 4 h, 21.1 m2·g-1 at 900 ℃ for 6 h. The three way catalysts prepared using Ce0.70Zr0.30O2 solid solutions as washcoat material show high catalytic performance. The light-off temperatures of CO, HC and NO are 244.6, 286.0 and 250.0 ℃, respectively. The operation window is in the A range 0.84 - 1.04.