Synthesis and study of nanostructured Ce-Zr-La-RE-O (RE=Y, Nd and Pr) quaternary solid solutions and their supported three-way catalysts

Publication date: 15 September 2017
Source:Materials & Design, Volume 130
Author(s): Yi Zhou, Jie Deng, Lei Xiong, Jianli Wang, Shandong Yuan, Hailong Zhang, Yaoqiang Chen
In this work, a series of nanostructured Ce-Zr-La-RE-O (RE=Y, Nd and Pr) quaternary solid solutions (CZLY, CZLN and CZLP) were synthesized via simultaneous co-precipitation with the assistance of lauric acid. The corresponding supported Pd-only three-way catalysts (Pd/CZLY, Pd/CZLN and Pd/CZLP) were also prepared by wet-impregnation method. The effects of Y, Nd and Pr on CeO2-ZrO2-La2O3-RE2O3 system and corresponding supported Pd-only three-way catalysts were investigated by X-ray diffraction (XRD), Raman, hydrogen-temperature programmed reduction (H2-TPR), N2 adsorption-desorption and X-ray photoelectron spectroscopy (XPS) characterizations. The results show that all the fresh samples form single phase structure, however, after being thermal aged at 1000°C, CZLN-a exhibits the best thermal stability which presents a remarkably low reduction peak temperature of 395°C and a high surface area of 42.6m²/g. The study of the interactions between Pd metal particles and supports indicates that Pd could selectively adsorb onto the surface Ce sites of different supporting materials by forming different chemical bonds. Pd/CZLN also exhibits superior three-way catalytic activity with respect to others, particularly, the light-off temperatures (T50) of C3H8, CO and NO for Pd/CZLN-a are as low as 339, 175 and 198°C, respectively.

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