Preparation of Ce_0.1+xTi_0.5-xAl_0.2 Y_0.1La_0.1O_1.8 and its application in three-way catalyst

Ce_0.1+xTi_0.5-xAl_0.2 Y_0.1La_0.1O_1.8 (0 ≤ x ≤ 0.4) mixed oxides were prepared by co-precipitation method and characterized by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption (BET), oxygen storage capacity (OSC), H₂-temperature programmed reduction (H₂-TPR) and NH₃-temperature programmed desorption (NH₃-TPD). The results of XRD revealed that there was only one single cubic phase in Ce_0.1+xTi_0.5-xAl_0.2 Y_0.1La_0.1O_1.8 system when x value increased from 0.2 to 0.4. The results of XPS showed that the ratio of superficial Ce⁴⁺/Ce³⁺ is maximal when x is 0.2. With the increase of Ce/Ti ratio, OSC is increased to a maximum value, and then gradually decreased. When x value is 0.2, the OSC reaches to 660μmol/g, and the reduction temperature of Ce⁴⁺ is the lowest according to the H₂-TPR test (616°C). In this paper, a series of Pt/Ce_0.1+xTi_0.5-xAl_0.2 Y_0.1La_0.1O_1.8 three-way catalysts were prepared and the catalytic activities of catalysts were investigated. The results revealed that Pt/Ce_0.3Ti_0.3Al_0.2 Y_0.1La_0.1O_1.8 exhibits excellent low-temperature catalytic activity. The light-off temperature of C₃H₈, CO and NO over Pt/Ce_0.3Ti_0.3Al_0.2 Y_0.1La_0.1O_1.8 is 236, 147 and 228°C, respectively.