A simple and effective method to synthesize Pt/CeO2 three-way catalysts with high activity and hydrothermal stability

Abstract

Abstract Developing three-way catalysts (TWCs) with improved activity and hydrothermal stability is essential for automotive exhaust treatment. Here, citric acid-assisted sol-gel method was used to prepare Pt/CeO2 TWCs, in order to obtain excellent activity and hydrothermal stability. The catalytic performance was evaluated on the conversions of pollutants CO, NOx and HC, and the catalysts were characterized using N2 adsorption-desorption, XRD, CO-adsorption, XPS and H2-TPR techniques. It is interesting to note that the Pt/CeO2 catalyst synthesized by sol-gel method (PC-sg) showed improved activity after 13 h exposure to steam and oxidizing atmosphere at 750 °C and exhibited comparable activity with the fresh catalyst (PC-im) prepared by impregnation method. Combined with characterization results, the improved performance for aged PC-sg catalysts is ascribed to the segregation of Pt out from ceria and dispersion on the surface of ceria after aging treatment, and the PC-sg catalysts had stronger metal-support interaction between metal and support to facilitate the creation of oxygen vacancies. The results obtained in this study showed a simple and effective method to synthesize TWCs with high activity and hydrothermal stability which provided valuable information for the design of advanced TWCs.