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Systems and methods of removing at least nitrogen oxides from an exhaust fluid generally include dividing a flow of an exhaust fluid comprising a concentration of nitric oxide into three types of flow-through cells. The first flow-through cell comprises a catalyst configured to reduce the nitric oxi

Systems and methods of removing at least nitrogen oxides from an exhaust fluid generally include dividing a flow of an exhaust fluid comprising a concentration of nitric oxide into three types of flow-through cells. The first flow-through cell comprises a catalyst configured to reduce the nitric oxide with a reductant to form a first feedstream comprising nitrogen containing species derived therefrom. The second flow-through cell comprises a catalyst configured to oxidize nitric oxide to form a second feedstream comprising nitrogen dioxide. The third flow-through cell does not change the nitric oxide concentration and form a third feedstream comprising nitric oxide. After flowing through the three different types of cells, the feedstreams are mixed to form a homogenous mixture and then fed to a catalyst bed configured to convert the nitrogen containing species, the nitric oxide, and the nitrogen dioxide to a fluid comprising nitrogen gas and water.

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What is claimed is: 1. A method of reducing nitrogen oxides from an exhaust fluid, the method comprising: dividing a flow of an exhaust fluid comprising a concentration of nitric oxide into three types of flow-through cells, wherein the first flow-through cell comprises a catalyst configured to red

What is claimed is: 1. A method of reducing nitrogen oxides from an exhaust fluid, the method comprising: dividing a flow of an exhaust fluid comprising a concentration of nitric oxide into three types of flow-through cells, wherein the first flow-through cell comprises a catalyst configured to reduce the nitric oxide with a reductant to form a first feedstream comprising nitrogen containing species, the second flow-through cell comprises a catalyst configured to oxidize nitric oxide to form a second feedstream comprising nitrogen dioxide, and the third flow-through cell does not change the nitric oxide concentration and forms a third feedstream comprising nitric oxide; mixing the first, second, and third feedstreams to form a homogenous mixture; and flowing the mixture into a catalyst bed configured to convert the nitrogen containing species, nitric oxide, and nitrogen dioxide to produce a treated exhaust fluid comprising nitrogen gas and water. 2. The method of claim 1, wherein the reductant is fed upstream and into the first flow-through cell. 3. The method of claim 1, wherein the first flow-through cell comprises a catalyst material selected from the group consisting of silver, gallium, indium, tin, gold, cobalt, nickel, zinc, copper, platinum, palladium, and oxides and alloys comprising at least one of the foregoing. 4. The method of claim 3, wherein the catalyst material further comprises an inorganic oxide support material selected from the group consisting of alumina, silica, zirconia, titania, and combinations comprising at least one of the foregoing. 5. The method of claim 1, wherein the reductant is a hydrocarbon reductant. 6. The method of claim 5, further comprising introducing a co-reductant with the reductant, wherein the co-reductant is hydrogen gas. 7. The method of claim 5, wherein the hydrocarbon reductant comprises a mixture comprising aliphatic hydrocarbons, aliphatic alcohols, hydrogen gas, or mixtures thereof. 8. The method of claim 1, wherein the exhaust fluid comprising a concentration of nitrogen oxides is at a temperature of about 150�� C. to about 600�� C. and the concentration of nitrogen oxides in the exhaust fluid is reduced. 9. The method of claim 1, wherein the first, second, and third flow-through cells are arranged in a honeycomb body. 10. The method of claim 1, wherein dividing the flow of the exhaust fluid into the three types of flow-through cells comprises simultaneously flowing the exhaust fluid through multiple cells of each type. 11. The method of claim 1, wherein the homogenous mixture comprises a 2:1:1 ratio of nitrogen containing species, nitric oxide, and nitrogen dioxide. 12. The method of claim 1, wherein the second flow-through cell comprises a catalyst material comprising a noble metal or a metal oxide. 13. The method of claim 1, further comprising injecting a nitrogen hydride reductant into the catalyst bed configured to convert the nitrogen containing species, nitric oxide, and nitrogen dioxide to produce the nitrogen gas and water, wherein the catalyst bed comprises a catalyst material selected from the group consisting of indium, copper, silver, zinc, cadmium, cobalt, nickel, iron, molybdenum, tungsten, titanium, vanadium, zirconium, and oxides and alloys comprising at least one of the foregoing. 14. The method of claim 13, wherein the nitrogen hydride is selected from the group consisting of ammonia and hydrazine. 15. The method of claim 1, wherein the nitrogen containing species derived from nitric oxide comprises alkyl nitrates of the general formulae RONO and RONO2, wherein R is an alkyl group; dimethylamine; hydrogen cyanide; ammonia; nitrous oxide; methyl amine; trimethylamine; ethylamine; acetonitrile, and mixtures thereof. 16. The method of claim 1, wherein dividing the flow of the exhaust fluid comprising a concentration of nitric oxide into the three types of flow-through cells comprises flowing about 40 to about 60 percent of the total volume of exhaust fluid through the first flow-through cell. 17. An exhaust conduit for removing at least nitrogen oxides from an exhaust gas, the exhaust conduit comprising: a first portion comprising at least three cells, the at least three cells comprising a first cell configured to reduce nitric oxide to nitrogen containing species; a second cell configured to oxidize nitric oxide to nitrogen dioxide; and a third cell configured to be non-reactive with nitric oxide; and wherein the first cell further comprises a reductant disposed upstream from and in fluid communication therewith; a second portion downstream from and in fluid communication with the first portion and configured to form a homogenous mixture of the nitrogen containing species, nitric oxide, and nitrogen dioxide from the first portion; and a third portion downstream from and in fluid communication with the second portion, the third portion configured to react the nitrogen containing species, nitric oxide, and nitrogen dioxide to form nitrogen gas and water. 18. The exhaust conduit of claim 17, wherein the first cell comprises a catalyst material selected from the group consisting of silver, gallium, indium, tin, gold, cobalt, nickel, zinc, copper, platinum, palladium, and oxides and alloys comprising at least one of the foregoing. 19. The exhaust conduit of claim 17, wherein the homogenous mixture comprises a 2:1:1 ratio of nitrogen containing species, nitric oxide, and nitrogen dioxide, respectively. 20. The exhaust conduit of claim 17, wherein the second cell comprises a catalyst material comprising a noble metal or a metal oxide. 21. The exhaust conduit of claim 17, wherein the third portion configured to react the nitrogen containing species, nitric oxide, and nitrogen dioxide to form nitrogen gas and water comprises an ammonia selective catalyst reduction bed and a nitrogen hydride reductant source in fluid communication therewith. 22. The exhaust conduit of claim 17, wherein the reductant comprises aliphatic hydrocarbons, aliphatic alcohols, hydrogen gas, or mixtures thereof.