Catalyst for catalytic reduction of nitrogen oxide and process for producing the same

摘要

A catalyst suitable for removing nitrogen oxides from an exhaust gas from a diesel engine or lean-burn type gasoline engine by a catalytic reduction and a process for producing it are disclosed. The catalyst for the catalytic reduction of nitrogen oxides comprises AG alone or both Ag and Ir as the catalytic active ingredient supported on a gamma -Al2O3 carrier containing 0.1 to 1.0% by weight of Ca. The amounts of Ag and Ir carried by the carrier are preferably 1.0 to 5.0% by eight and not more than 0.05% by weight, respectively, based on the carrier. With the catalyst for the catalytic reduction of nitrogen oxides, nitrogen oxides even in an exhaust gas containing an excess amount of oxygen such as that from a diesel engine or lean-burn type gasoline engine can be efficiently removed.