Patent attributes
A NOx trap, and its use in an exhaust system for internal combustion engines, is disclosed. The NOx trap comprises a substrate and three layers on the substrate. The first layer comprises a first platinum group metal, a first NOx storage component, and a first support; the second layer comprises a second platinum group metal, a second NOx storage component, and a second support; and the third layer comprises rhodium and a third support. The platinum group metal loading in the first layer is from 1 to 40 percent of the platinum group metal loading in the second layer. In addition, the first NOx storage component and the second NOx storage component are the same, and the first support and the second support are the same. The NOx trap is less prone to deactivation over numerous desulfation/NOx trap regeneration cycles.
