A BARIUM SUBSTITUTED-SULFUR TOLERANT LEAN NOx TRAP

The present invention provides a composition and method for storing and reducing NOx from lean burn internal combustion engines. The present invention uses composite metal oxides, in spinel structure, in conjunction with the typical lean NOx trap formulation to form an integrated lean NOx trap. The composite metal oxides in spinel structure act primarily as a SOx trapping element and also secondarily as a NOx trapping element within the integrated LNT. In this integrated LNT, the sulfur is trapped and released in a way that does not allow the sulfur to go to the primary NOx trapping element an alkali or earth metal - and thus prevents the integrated lean NOx trap from becoming poisoned, thereby leaving more reactive sites for NOx trapping and conversion.