Abstract: A NOx trap comprises components comprising at least one platinum group metal, at least one NOx storage material and bulk ceria or a bulk cerium-containing mixed oxide deposited uniformly in a first layer on a honeycombed substrate monolith, the components in the first layer having a first, upstream, zone having increased activity relative to a second, downstream zone for oxidising hydrocarbons and carbon monoxide, and a second, downstream, zone having increased activity to generate heat during a desulphation event, relative to the first zone, wherein the second zone comprises a dispersion of rare earth oxide, wherein the rare earth oxide loading in the second zone is greater than the loading in the first zone. An exhaust system for a lean burn internal combustion engine, a vehicle comprising a lean burn internal combustion engine and the exhaust system and methods of making the NOx trap are also disclosed.

Abstract: A NOx absorber catalyst comprising a substrate monolith coated with one or more washcoat layers and comprising a first component comprising a nitrogen oxide storage component, at least one precious metal and a dispersed rare earth oxide supported on a refractory support material, and a second component comprising a precious metal supported on a bulk reducible oxide that is substantially free of nitrogen oxide storage material, wherein the precious metal present in the second component comprises Pt, Pd or a combination of both Pt and Pd and wherein the bulk reducible oxide is an oxide, a composite oxide or a mixed oxide comprising at least one of manganese, iron, cobalt, copper, tin or cerium.

Abstract: A NOx absorber catalyst comprising an extruded solid body comprises either: (A) 10-95% by weight of at least one binder/matrix component; and 5-90% by weight of a zeolitic molecular sieve, a non-zeolitic molecular sieve or a mixture of any two or more thereof, which catalyst comprising at least one metal comprising (a) at least one precious metal; and (b) at least one alkali metal or at least one alkaline earth metal, wherein (a) and (b) are carried in one or more coating layer(s) on a surface of the extruded solid body; or (B) 10-95% by weight of at least one binder/matrix component; and 5-80% by weight optionally stabilized ceria, which catalyst comprising at least one metal comprising (a) at least one precious metal; and (b) at least one alkali metal or at least one alkaline earth metal.

Abstract: A NOx absorber catalyst comprising a substrate monolith coated with one or more washcoat layers and comprising a first component comprising a nitrogen oxide storage component, at least one precious metal and a dispersed rare earth oxide supported on a refractory support material, and a second component comprising a precious metal supported on a bulk reducible oxide that is substantially free of nitrogen oxide storage material, wherein the precious metal present in the second component comprises Pt, Pd or a combination of both Pt and Pd and wherein the bulk reducible oxide is an oxide, a composite oxide or a mixed oxide comprising at least one of manganese, iron, cobalt, copper, tin or cerium.

Abstract: A NOx absorber catalyst comprising an extruded solid body comprises either: (A) 10-95% by weight of at least one binder/matrix component; and 5-90% by weight of a zeolitic molecular sieve, a non-zeolitic molecular sieve or a mixture of any two or more thereof, which catalyst comprising at least one metal comprising (a) at least one precious metal; and (b) at least one alkali metal or at least one alkaline earth metal, wherein (a) and (b) are carried in one or more coating layer(s) on a surface of the extruded solid body; or (B) 10-95% by weight of at least one binder/matrix component; and 5-80% by weight optionally stabilised ceria, which catalyst comprising at least one metal comprising (a) at least one precious metal; and (b) at least one alkali metal or at least one alkaline earth metal.

Abstract: A method of reducing nitrogen oxides (NOx) present in a lean gas stream comprising nitric oxide (NO) comprises the steps of: (i) net adsorbing NO per se from the lean gas stream in an adsorbent comprising palladium and a cerium oxide at below 200° C.; (ii) thermally net desorbing NO from the NO adsorbent in a lean gas stream at 200° C. and above; and (iii) catalytically reducing NOx on a catalyst other than the NO adsorbent with a reductant selected from the group consisting of a hydrocarbon reductant, a nitrogenous reductant, hydrogen and a mixture of any two or more thereof. A system for carrying out such a method is also disclosed.

Abstract: A method of reducing nitrogen oxides (NOx) present in a lean gas stream comprising nitric oxide (NO) comprises the steps of: (i) net adsorbing NO per se from the lean gas stream in an adsorbent comprising palladium and a cerium oxide at below 200° C.; (ii) thermally net desorbing NO from the NO adsorbent in a lean gas stream at 200° C. and above; and (iii) catalytically reducing NOx on a catalyst other than the NO adsorbent with a reductant selected from the group consisting of a hydrocarbon reductant, a nitrogenous reductant, hydrogen and a mixture of any two or more thereof. A system for carrying out such a method is also disclosed.

Abstract: A NOx trap comprises components comprising at least one platinum group metal, at least one NOx storage material and bulk ceria or a bulk cerium-containing mixed oxide deposited uniformly in a first layer on a honeycombed substrate monolith, the components in the first layer having a first, upstream, zone having increased activity relative to a second, downstream zone for oxidising hydrocarbons and carbon monoxide, and a second, downstream, zone having increased activity to generate heat during a desulphation event, relative to the first zone, wherein the second zone comprises a dispersion of rare earth oxide, wherein the rare earth oxide loading in the second zone is greater than the loading in the first zone. An exhaust system for a lean burn internal combustion engine, a vehicle comprising a lean burn internal combustion engine and the exhaust system and methods of making the NOx trap are also disclosed.