| abstract |
Herein disclosed are compositions for passive NOx adsorption and oxidation that include at least a manganese-based oxide and one or more promoter materials and methods for making and using said compositions. The promotor materials may include a rare earth, transition, or main group metal. The compositions may be used in NOx emission control system and adsorbs NOx compounds at low temperatures and then release NOx at higher temperatures, where the NOx can be oxidized, without the hybridized MnOX composition breaking down. The compositions are capable of maintaining a sufficiently large surface area at high temperatures found in the emissions gas streams of internal combustion engines necessary for the complete elimination of NOx. |