Abstract: Catalysts, methods, and systems for treating diesel engine exhaust streams are described. In one or more embodiments, the catalyst comprises platinum, a second metal from one of the groups VB, VIB, VIIB, VIIIB, IB, or IIB of the periodic table, a refractory metal oxide, and a zeolite, the oxidation catalyst already being effective to remove ammonia at temperatures less than about 300° C. and exhibiting no significant decrease in ammonia oxidation efficiency upon hydrothermal aging. A method aspect includes first passing a vehicle's engine exhaust stream through a NOx abatement catalyst; and passing the exhaust stream exiting the NOx abatement catalyst and containing ammonia through the ammonia oxidation catalyst. Systems including such catalysts are also provided.

Abstract: Zeolite catalysts and systems and methods for preparing and using zeolite catalysts having the CHA crystal structure are disclosed. The catalysts can be used to remove nitrogen oxides from a gaseous medium across a broad temperature range and exhibit hydrothermal stable at high reaction temperatures. The zeolite catalysts include a zeolite carrier having a silica to alumina ratio from about 15:1 to about 256:1 and a copper to alumina ratio from about 0.25:1 to about 1:1.

Abstract: Zeolite catalysts and systems and methods for preparing and using zeolite catalysts having the CHA crystal structure are disclosed. The catalysts can be used to remove nitrogen oxides from a gaseous medium across a broad temperature range and exhibit hydrothermal stable at high reaction temperatures. The zeolite catalysts include a zeolite carrier having a silica to alumina ratio from about 15:1 to about 256:1 and a copper to alumina ratio from about 0.25:1 to about 1:1.

Abstract: Catalysts, methods, and systems for treating diesel engine exhaust streams are described. In one or more embodiments, the catalyst comprises platinum, a second metal from one of the groups VB, VIIB, VIIB, VIIIB, IB, or IIB of the periodic table, a refractory metal oxide, and a zeolite, the oxidation catalyst already being effective to remove ammonia at temperatures less than about 300° C. and exhibiting no significant decrease in ammonia oxidation efficiency upon hydrothermal aging. A method aspect includes first passing a vehicle's engine exhaust stream through a NOx abatement catalyst; and passing the exhaust stream exiting the NOx abatement catalyst and containing ammonia through the ammonia oxidation catalyst. Systems including such catalysts are also provided.

Abstract: Zeolite catalysts and systems and methods for preparing and using zeolite catalysts having the CHA crystal structure are disclosed. The catalysts can be used to remove nitrogen oxides from a gaseous medium across a broad temperature range and exhibit hydrothermal stable at high reaction temperatures. The zeolite catalysts include a zeolite carrier having a silica to alumina ratio from about 15:1 to about 256:1 and a copper to alumina ratio from about 0.25:1 to about 1:1.