Enhanced thermal stability of CeO2-ZrO2-Nd2O3 composite by adding surfactant and its supported Rh-only three-way catalyst

Abstract

Ceria-zirconia-neodymia composites are synthesized by a co-precipitation combined with mechanical mixing of trialkyl amine (N235, N (CnH2n+1), n=8–10) process and the effect of the novel surfactant N235 on the properties of ceria-zirconia-neodymia composites and their supported Rh-only three-way catalysts are investigated. The physicochemical properties of the samples before and after aging treatment are characterized by N2 adsorption-desorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), H2-temperature programmed reduction (H2-TPR), oxygen storage capacity (OSC), scanning electron microscopy (SEM), transmission electron microscopy (TEM), particle size distribution analysis and CO chemisorption. The results indicate that the introduction of surfactant N235 is beneficial to form loose and porous morphology, which contributes to the high surface area, large OSC, superior redox property and high Rh dispersion, and thus the improved catalytic activity for Rh-only three-way catalyst is obtained. The more dosage of N235, the superior catalytic performance for Rh catalyst is. The modified support material (the molar ratio of N235 and total metals is 0.21:1) displays relatively better textural, structural, redox and OSC properties, and the corresponding fresh (Rh/CZN3f) and aged (Rh/CZN3a) catalysts deliver superior catalytic activity.