| abstract |
An exhaust gas cleaner is constituted of an Ag catalyst carrying nan Ag component and a base metal catalyst carrying a Cu component and noptionally W, V, Mo components, and a noble metal catalyst carrying a nnoble metal component. The base metal catalyst and the noble metal ncatalyst may be physically mixed to form a mixed catalyst. Another nexhaust gas cleaner is constituted of the first Ag catalyst carrying an Ag ncomponent, a second Ag catalyst carrying an Ag component, a base nmetal catalyst carrying a Cu component and optionally W, V, Mo ncomponents, and a noble metal catalyst carrying a noble metal ncomponent. The second Ag catalyst carries the Ag component in an namount larger than that of the first Ag catalyst. The noble metal ncatalyst may be physically mixed with the base metal catalyst to form a mixed ncatalyst. The exhaust gas cleaner may effectively remove nitrogen oxides nin a wide temperature range of exhaust gas. |