Effects of precipitate aging time on the cerium-zirconium composite oxides
Abstract Cerium-zirconium composite oxides with high performance were synthesized by a co-precipitation method, using zirconium oxychloride and rare earth chloride as raw materials. The effects of precipitate aging time on the properties of cerium-zirconium composite oxides were investigated. The prepared cerium-zirconium composite oxides were characterized by X-ray diffraction (XRD), BET specific surface area, pulsed oxygen chemical adsorption, H 2 temperature-programmed-reduction (H 2 -TPR), scanning electron microscopy (SEM), etc. The results showed that the precipitate aging time caused great effects on the properties of cerium zirconium composite oxides. With the increase of aging time, the cerium zirconium composite oxides showed enhanced specific surface area, good thermal stability, and high oxygen storage capacity (OSC). The best performance sample was obtained while the precipitate aging time up to 48 h, with the specific surface area of 140.7 m 2 /g, and OSC of 657.24 μmolO 2 /g for the fresh sample. Even after thermal aged under 1000 °C for 4 h, the aged specific surface area was 41.6 m 2 /g, moreover with a good OSC of 569.9 μmolO 2 /g.