| 摘要 |
A catalyst capable of removing nitrogen oxides contained in exhaust gas satisfactorily, which comprises a monolith carrier and an under layer containing a cerium oxide-containing catalyst component (A) and an upper layer containing a catalyst component (B) containing both at least one member selected from the group consisting of copper, manganese, iron, cobalt and nickel and zeolite, both of which layers cover the carrier. The catalyst exerts oxidation catalysis due to the catalyst component (B) contained the upper layer to accelerate efficiently the oxidation of nitrogen oxides contained in exhaust gas, particularly, the oxidation of nitrogen monoxide (NO) into nitrogen dioxide (NO2), and the nitrogen dioxide thus formed is adsorbed by the cerium oxide contained in the under layer. Further, the catalyst can exert satisfactory catalytic activity even at a low temperature range of about 100°C, e.g., 80 to 150°C, so that the catalyst can significantly reduce or remove nitrogen oxides (NOx) contained in exhaust gas even at low temperature.
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