| 摘要 |
PROBLEM TO BE SOLVED: To heighten the stability at a high temperature and at the same time, suppress sintering, by forming a first layer of a high temperature-stable ceramic with a small specific surface area alteration in a specified high temperature range and a second layer of an amorphous Al2 O3 , and making catalyst components carried on the second layer. SOLUTION: In the catalyst for treating NOX emitted out of internal combustion engine of automobile, a first layer of a high temperature stable ceramic with a small specific surface area alteration in a temperature range not lower than 900 deg.C is formed. That is, the first layer is formed as a core material 1 using a ceramic powder of such as α-Al2 O3 , SiO2 , etc. A second layer 2 of one or more materials selected from amorphous Al2 O3 , La2 O3 -Al2 O3 , etc., is then formed on the surface of the core material 1 by sol-gel method and Pt is deposited on the second layer 2 to give a desired catalyst. In this case, it is preferable that the second layer 2 formed on the surface of the core material 1 is made to have a high specified surface area and improved heat resistance by sol-gel method. |
