COMPOUND OXIDE AND CATALYST FOR CLEANING EXHAUST GAS

摘要

PROBLEM TO BE SOLVED: To suppress the deterioration of a carrier and the grain growth of Pt at the time of high temperature endurance for a catalyst for cleaning an exhaust gas.

SOLUTION: The catalyst for cleaning the exhaust gas is obtained by supporting Pt on a CeO2-ZrO2-Al2O3compound oxide in which Al/(Ce+Zr) is within a range of 1/20 to 50/20. The grain growth of CeO2-ZrO2particles is suppressed and the reduction of the specific surface area at a temperature close to 1,000°C is suppressed by allowing Al2O3to coexist. The low-temperature activity is enhanced by heat treatment at a high temperature, because Ce is made easily reducible and the oxygen release rate is enhanced. Further, the grain growth of Pt can be suppressed while maintaining heat resistance of the carrier by optimizing the ratio of Al2O3to CeO2-ZrO2.

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