Study On Properties Of Ceria-based Oxygen Storage Material Prepared By Co-precipatation

Oxygen storage materials (OSM)were prepared by co-precipitation. XRD,OSC,TPR,BET were used to study properties of samples as obtained. Results showed that increasing the content of cerium can improve the OSC, but harm its thermal stability. When the ratio of Cerium to Zirconium was 1:1, the OSM had better OSC than others. The OSM prepared by different precipitation method had the same structure and better OSC, but had quite different texture. Precipitating agent also influenced the texture and the OSM precipitated by ammonia had higher specific surface area and higher thermal stability.In the case of OSM precipitated by ammonia, detail investigation was carried out to study the influence of preparation conditions such as pH value, reactants' concentration and maturing temperature. The OSM obtained under optimized conditions had high OSC at low temperature, high specific surface area and good thermal stability.The OSM precipitated by ammonium carbonate was also studied. It was found the pH value greatly influenced the process of precipitation while the OSM matured for a long period under higher temperature would be beneficial to higher specific surface area but lead to a quite low OSC. The concentration of ammonium carbonate had great effect on properties of OSM. Compared with ammonia, OSM prepared by ammonium carbonate as precipitation had worse properties.