Catalysts, systems and methods are described to reduce NO.sub.x emissions of an internal combustion engine. In one embodiment, an emissions treatment system for an exhaust stream is provided having a catalyst comprising silver on a particulate alumina support, the silver having a diameter of less than about 20 nm. Methods of manufacturing catalysts are described in which ionic silver is impregnated on particulate hydroxylated alumina particles.
GOVERNMENT CONTRACT RIGHTS
The U.S. Government has a paid-up license in this invention and the right in limited circumstances to require the patent owner to license others on reasonable terms as provided for by the terms of DE-FC26-02NT41218 awarded by the U.S. Department of Energy.