A NOx trap catalyst is disclosed. The NOx trap catalyst comprises a noble metal, a NOx storage component, a support, and a first ceria-containing material. The first ceria-containing material is pre-aged prior to incorporation into the NOx trap catalyst, and may have a surface area of less than 80 m2/g. The invention also includes exhaust systems comprising the NOx trap catalyst, and a method for treating exhaust gas utilizing the NOx trap catalyst.