NOX TRAP Russian patent published in 2015 - IPC B01D53/94 B01J23/63 

FIELD: chemistry.

SUBSTANCE: invention relates to a NOx trap, i.e. NOx adsorber catalyst, which is a part of exhaust gas aftertreatment systems for internal combustion engines. The catalyst comprises a honeycombed substrate monolith. The first layer substrate 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 and a dispersion of rare earth oxides. The first layer has a first, upstream, zone and a second, downstream zone. The loading of the dispersion of rare earth oxide in the first, upstream, zone, g/l, is in the range 0-30% of the loading of the dispersion of the rare earth oxide in the second, downstream, zone. The first, upstream, zone has increased activity relative to a second, downstream zone for oxidising hydrocarbons and carbon monoxide. And a second, downstream, zone has increased activity to generate heat during a desulphation event, relative to the first, upstream, zone.

EFFECT: improved NOx reduction at lower temperatures, offering the ability to release trapped sulphur more efficiently and/or with a less demanding desulphation event.

14 cl, 2 dwg, 1 tbl, 3 ex