CATALYST FOR GASOLINE LEAN BURN ENGINES WITH IMPROVED NH3-FORMATION ACTIVITY

The present invention relates to a catalyst comprising a substrate and a catalyst coating, the catalyst coating comprising two or more layers, said layers comprising: (a) a first layer provided on the substrate, said first layer comprising Pd and Rh; and (b) a second layer provided on the first layer, said second layer comprising Pt and/or Pd; the first and second layers each further comprising: one or more particulate support materials; one or more oxygen storage component (OSC) materials; and one or more nitrogen oxide storage materials comprising one or more elements selected from the group of alkali and/or alkaline earth metals, wherein the total amount of alkali and alkaline earth metals comprised in the one or more nitrogen oxide storage materials contained in the catalyst ranges from 0.18 to 2.0 g/in³ calculated as the respective alkali metal oxides M2O and alkaline earth metal oxides MO, as well as to a method for the production of a catalyst, and to a process for the treatment of a gas stream, in particular of an exhaust gas stream resulting from an internal combustion engine.