Tohoku Univ. Technology : Oxygen storage material, catalyst for cleaning exhaust gas, and method for manufacturing oxygen storage material : T20-3135

Oxygen storage material comprising oxide containing κ phase having large specific surface area

CeO2-ZrO2 composite oxide with excellent oxygen storage capacity (OSC) has been used as an atmosphere control material for ternary catalysts used to purify exhaust gas from automobiles. Among CeO2-ZrO2 composite oxides, κ phase (cubic pyrochlore like structure) is known to exhibit the highest OSC. However, due to the high temperature required for the synthesis process of κ phase, the specific surface area is significantly reduced and practical application of κ phase is difficult.　 In the present invention, it has become possible to provide an atmosphere-controlling material consisting of an oxide containing κ phase, in which the decrease in the specific surface area is greatly suppressed by the synthesis process at a lower temperature than in the conventional process. The low temperature is realized by adding Fe oxide during the synthesis of the complex oxide. The material by this synthesis process shows a clear XRD pattern assigned to the κ phase and has a specific surface area of 3 m2/g or more. This shows the possibility of practical application of the κ phase, and it can be said that the technology is expected to improve the purification ability of exhaust gas.

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