| 摘要 |
PURPOSE:To improve cleaning efficiency for a waste gas in a wide range of temp. and to provide a practical cleaning method for cleaning waste gas from a motor car. CONSTITUTION:In a waste gas cleaning catalyst provided at the exhausting path for waste gas, a primary catalyst layer 3 consisting of a catalyst containing a noble metal which cleans NOx when temp. of a waste gas is low, and reacts with hydrocarbon, is formed on a carrier 2. Moreover, secondary catalyst layer 4 consisting of a zeolite which clean NOx when temp. of the waste gas is high, is formed upon the primary catalyst layer 3. |
