THERMALLY STABLE LEAN NOx TRAP

A thermally stable NOx trap composition comprising:

• a support material;
• a NOx absorber material;
• an oxide selected from the group consisting of oxides of magnesium, oxides of manganese, and combinations thereof in sufficient contact with the NOx absorber that a NOx trap incorporating the NOx trap composition has a NOx storage efficiency of at least 5% at a temperature of 400° C. after aging of the NOx trap;
• and
• a precious metal in contact with the NOx material.

A method of removing harmful gases from an automobile exhaust containing NOx, CO, and hydrocarbons the method comprising:

• contacting a NOx trap composition with a first exhaust gas mixture at a temperature of at least 200° C., the first exhaust gas mixture comprising exhaust gases from an internal combustion engine operating in a fuel-lean condition and the NOx trap composition comprising:
• a precious metal;
• barium oxide;
• a oxide that inhibits the decrease in NOx storing ability of the barium oxide;
• and
• a support material;
• and
• contacting the NOx trap composition with a second exhaust gas composition, the second exhaust gas mixture comprising exhaust gases from an internal combustion engine operating in a fuel-rich condition.