| 摘要 |
PROBLEM TO BE SOLVED: To prevent the lowering of catalyst activities particularly concerning the specified catalyst set temperature condition and use for a long period of time under the coexistence of a water content and a sulfur oxide by using γ-alumina as a carrier and carrying titanium, silver and cobalt on the carrier. SOLUTION: As a carrier, γ-alumina is used, and titanium, silver and cobalt are laminated and carried on a carrier preferably from the carrier side successively in the above order for a catalyst, and a nitrogen oxide in engine exhaust gas containing the amount of oxygen excessive from the viewpoint of theoretical combustion amount is removed under the presence of an organic compound such as a fuel by using the catalyst. The denitration capability can be maintained for a long period of time even under the coexistence of the water content and a sulfur oxide. Particularly even when the catalyst set temperature is 400$<= or under, the denitration capability is not lowered to retain the catalyst activities, as titanium is carried on. Superior denitration effects, therefore, can be obtained in all exhaust gas temperatures all through the low temperature to the high temperature. |
