Effect of grain size on thermal stability and oxygen storage capacity of Ce0.17Zr0.73La0.02Nd0.04Y0.04O2 solid solutions

Abstract

Nanostructured CeO2-ZrO2 materials are an irreplaceable constituent in catalytic systems for automobile exhaust purification due to their unique oxygen storage capacity (OSC). However, traditional CeO2-ZrO2 materials are easy to sinter at high temperature, which causes a sharp decrease of OSC. In this paper, La3+, Nd3+ and Y3+ are chosen as dopants for CeO2-ZrO2 to improve anti-sintering and OSC properties. The Ce0.17Zr0.73La0.02Nd0.04Y0.04O2 powders (CZLNY) were prepared by co-precipitation method. The effects of grain sizes with different mixed chlorinated solution concentrations on performances were investigated. X-ray diffraction (XRD) and transmission electron micrograph (TEM) were performed to calculate the grain sizes of CZLNY. The specific surfaces, OSC and redox properties were investigated by N2 adsorption/desorption and temperature programmed reduction (H2-TPR). The results show that introducing La3+, Nd3+ and Y3+ into CeO2-ZrO2 lattice can improve the stability of phase structure and anti-sintering ability. Moreover, low concentration of mixed chlorinated solution remarkably improves structural and textural properties of CZLNY. Relatively large fresh grain exhibits superior thermal stability and OSC under the condition of being calcined at 800 °C for 3 h. The specific surface and OSC are 42.37 m2/g and 333.13 μmol/g after calcining at 1000 °C for 10 h, respectively. This is owing to the low sintered driving force of large grain and long-range migration energy of large pores during the sintering process, which are beneficial to the stability of structure in CZLNY materials.