| 摘要 |
PROBLEM TO BE SOLVED: To provide high NOx treatment efficiency by using a catalyst for exhaust gas cleaning comprising a zeolite bearing Pt and CeO2 with a specified average crystal particle diameter, using CeO2 bearing Pr as the CeO2 of the catalyst, and setting Pr deposition amount within a specified range. SOLUTION: In this catalyst for exhaust gas cleaning comprises a zeolite bearing Pt and CeO2 with a specified average crystal particle diameter D satisfying D>=13.0 nm, using CeO2 carry Pr is used as the CeO2 of the catalyst and the Pr deposition amount is set to satisfy 3 wt.% <=Pr<=10 wt.%. By depositing Pr on CeO2 , the CeO2 crystal is strained and the specific surface area of Pr- bearing CeO2 becomes wide as compared with that of CeO2 , so that the NOx absorption capacity of the Pr-bearing CeO2 in a high temperature range of an exhaust gas can be increased. Consequently, NOx treatment efficiency in a high temperature range of an exhaust gas, in other words, high temperature NOx treatment efficiency can be improved. |
