CATALYST FOR CLEANING EXHAUST GAS

摘要

PROBLEM TO BE SOLVED: To provide a catalyst for cleaning exhaust gas, which has on a honeycomb carrier a catalyst layer containing an oxygen storage material containing cerium, zirconium and rare earth elements excluding cerium and the heat resistance and oxygen storage ability of which are improved simultaneously to improve the cleaning performance of the catalyst.

SOLUTION: The mass ratio shown by ZrO2/(CeO2+ZrO2+Nd2O3) in a Ce-Zr-Nd compound oxide contained in the lower catalyst layer is ≤70 mass% and the mass ratio in the upper catalyst layer is made larger than that in the lower catalyst layer.

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