Preparation of Mixed Oxide Powders in the System CeO_2-MO_x (M = Transition and Rare Earth Metals) by Coprecipitation Method for the Purification Catalysts of Automotive Emission

摘要

Powders in the CeO_2-ZrO_2-MO_x system were prepared by coprecipitation method. Influence of adding a third components MO_x of transition metal oxides and rate earth metal oxides on the specific surfaace area (SA) and oxygen storage capacity (OSC) were investigated. It was found that transition metal oxides decrease drastically both SA and OSC values at 1000 deg C. On the other hand, rare earth metal oxides slightly decreased OSC values. The OSC values of the 20CeO_2-(80-y)ZrO_2-yMO_x powders with y = 0-20 mol% LaO_1.5, showed a maximum around 6 mol% LaO_1.5. In the CeO_2-ZrO_2-MO_x system, 20CeO_2·6LaO_1.5 (mol%) powders exhibited the most efficient performance with a high thermal stability up to 1000 deg C.