| 摘要 |
PURPOSE:To enhance heat resistance by suppressing the sintering of a transition metal at high temp., in a catalyst for purifying exhaust gas obtained by supporting a transition metal on metal-containing silicate by ion exchange, by supporting copper oxide on metal-containing silicate in a dispersed state. CONSTITUTION:In a catalyst for purifying exhaust gas obtained by supporting a transition metal on metal-containing silicate by ion exchange, copper oxide is dispersed in and supported on metal-containing silicate. This catalyst is reduced in the lowering of an NOx purifying ratio even after heating by the presence of a very small amount of copper oxide because a very small amount of copper oxide suppresses the free movement of the transition metal ion supported on metal-containing silicate by ion exchange and, as a result, the sintering of the transition metal ion is prevented and catalytic activity is kept. Since copper oxide has high oxidation accelerating capacity as compared with a segregated or sintered transition metal ion, the oxidation of CO or HC is accelerated a as a result, the reduction of NOx is smoothly advanced. |
