Patent ID: 6193942
Filing Date: 2001-02-27
Classification: B01D,B01J,F02B,Y02T

Abstract:
A method for the removal of nitrogen oxides in a diesel engine exhaust gas, which comprises exposing to a catalyst a diesel engine exhaust gas whose HC/NO.sub.x molar ratio is in the range of 0.5 to 20 (HC reduced to methane concentration), said catalyst comprising a refractory three-dimensional structure coated with a copper-containing refractory inorganic oxide powder comprising deposited copper, the copper content, as element, being in the range of 5-50% by weight based on said zirconia powder, and a catalytically active oxide of at least one metal selected from the group consisting of tungsten, gallium, nickel, manganese, iron, and cobalt, in the range of 2 to 40% by weight based on the copper, as element, on a zirconia powder, wherein said zirconia powder has a BET specific surface area in the range of 50 to 200 m.sup.2 /g and an average primary particle diameter in the range of 50 to 200 .ANG..