| abstract |
An exhaust gas cleaner comprises a first Ag catalyst, a second Ag catalyst, a transition metal catalyst selected from a Pt catalyst, a W catalyst, a W+Pt catalyst and a mixed catalyst of the Pt catalyst and the W catalyst. The second Ag catalyst and the Pt catalyst may be physically mixed together to form a mixed catalyst. Another exhaust gas cleaner comprises an Ag catalyst, a Cu catalyst and a W+Pt catalyst. The Cu catalyst and the W+Pt catalyst may be physically mixed together to form a mixed catalyst. Still another exhaust gas cleaner comprises a mixed catalyst of an Ag catalyst and a Cu catalyst. The exhaust gas cleaner may effectively remove nitrogen oxides from a wide temperature range of exhaust gases. |